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Research involving Lowell Observatory staff 2011
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  1. Cushing, M., Kirkpatrick, J., Gelino, C., Griffith, R., Skrutskie, M., Mainzer, A., Marsh, K., Beichman, C., Burgasser, A., Prato, L., Simcoe, R., Marley, M., Saumon, D., Freedman, R., Eisenhardt, P., Wright, E., 2011, ApJ, 743, 50, The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE)
    We present the discovery of seven ultracool brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Near-infrared spectroscopy reveals deep absorption bands of H2O and CH4 that indicate all seven of the brown dwarfs have spectral types later than UGPS J072227.51-054031.2, the latest-type T dwarf currently known. The spectrum of WISEP J182831.08+265037.8 is distinct in that the heights of the J- and H-band peaks are approximately equal in units of f , so we identify it as the archetypal member of the Y spectral class. The spectra of at least two of the other brown dwarfs exhibit absorption on the blue wing of the H-band peak that we tentatively ascribe to NH3. These spectral morphological changes provide a clear transition between the T dwarfs and the Y dwarfs. In order to produce a smooth near-infrared spectral sequence across the T/Y dwarf transition, we have reclassified UGPS 0722-05 as the T9 spectral standard and tentatively assign WISEP J173835.52+273258.9 as the Y0 spectral standard. In total, six of the seven new brown dwarfs are classified as Y dwarfs: four are classified as Y0, one is classified as Y0 (pec?), and WISEP J1828+2650 is classified as >Y0. We have also compared the spectra to the model atmospheres of Marley and Saumon and infer that the brown dwarfs have effective temperatures ranging from 300 K to 500 K, making them the coldest spectroscopically confirmed brown dwarfs known to date.
  2. Mainzer, A., Grav, T., Bauer, J., Masiero, J., McMillan, R., Cutri, R., Walker, R., Wright, E., Eisenhardt, P., Tholen, D., Spahr, T., Jedicke, R., Denneau, L., DeBaun, E., Elsbury, D., Gautier, T., Gomillion, S., Hand, E., Mo, W., Watkins, J., Wilkins, A., Bryngelson, G., Del Pino Molina, A., Desai, S., Gomez Camus, M., Hidalgo, S., Konstantopoulos, I., Larsen, J., Maleszewski, C., Malkan, M., Mauduit, J., Mullan, B., Olszewski, E., Pforr, J., Saro, A., Scotti, J., Wasserman, L., 2011, ApJ, 743, 156, NEOWISE Observations of Near-Earth Objects: Preliminary Results
    With the NEOWISE portion of the Wide-field Infrared Survey Explorer (WISE) project, we have carried out a highly uniform survey of the near-Earth object (NEO) population at thermal infrared wavelengths ranging from 3 to 22 m, allowing us to refine estimates of their numbers, sizes, and albedos. The NEOWISE survey detected NEOs the same way whether they were previously known or not, subject to the availability of ground-based follow-up observations, resulting in the discovery of more than 130 new NEOs. The survey's uniform sensitivity, observing cadence, and image quality have permitted extrapolation of the 428 near-Earth asteroids (NEAs) detected by NEOWISE during the fully cryogenic portion of the WISE mission to the larger population. We find that there are 981 19 NEAs larger than 1 km and 20,500 3000 NEAs larger than 100 m. We show that the Spaceguard goal of detecting 90% of all 1 km NEAs has been met, and that the cumulative size distribution is best represented by a broken power law with a slope of 1.32 0.14 below 1.5 km. This power-law slope produces ~13, 200 1900 NEAs with D > 140 m. Although previous studies predict another break in the cumulative size distribution below D ~ 50-100 m, resulting in an increase in the number of NEOs in this size range and smaller, we did not detect enough objects to comment on this increase. The overall number for the NEA population between 100 and 1000 m is lower than previous estimates. The numbers of near-Earth comets and potentially hazardous NEOs will be the subject of future work.
  3. Jensen, A., Redfield, S., Endl, M., Cochran, W., Koesterke, L., Barman, T., 2011, ApJ, 743, 203, A Survey of Alkali Line Absorption in Exoplanetary Atmospheres
    We obtained over 90 hr of spectroscopic observations of four exoplanetary systems with the Hobby-Eberly Telescope. Observations were taken in transit and out of transit, and we analyzed the differenced spectrai.e., the transmission spectrato inspect it for absorption at the wavelengths of the neutral sodium (Na I) doublet at 5889, 5895 and neutral potassium (K I) at 7698. We used the transmission spectrum at Ca I 6122which shows strong stellar absorption but is not an alkali metal resonance line that we expect to show significant absorption in these atmospheresas a control line to examine our measurements for systematic errors. We use an empirical Monte Carlo method to quantify these systematic errors. In a reanalysis of the same data set using a reduction and analysis pipeline that was derived independently, we confirm the previously seen Na I absorption in HD 189733b at a level of (- 5.26 1.69) 10-4 (the average value over a 12 A integration band to be consistent with previous authors). Additionally, we tentatively confirm the Na I absorption seen in HD 209458b (independently by multiple authors) at a level of (- 2.63 0.81) 10-4, though the interpretation is less clear. Furthermore, we find Na I absorption of (- 3.16 2.06) 10-4 at <3 in HD 149026b; features apparent in the transmission spectrum are consistent with real absorption and indicate this may be a good target for future observations to confirm. No other results (Na I in HD 147506b and Ca I and K I in all four targets) are significant to >=3, although we observe some features that we argue are primarily artifacts.
  4. Kirkpatrick, J., Cushing, M., Gelino, C., Griffith, R., Skrutskie, M., Marsh, K., Wright, E., Mainzer, A., Eisenhardt, P., McLean, I., Thompson, M., Bauer, J., Benford, D., Bridge, C., Lake, S., Petty, S., Stanford, S., Tsai, C., Bailey, V., Beichman, C., Bloom, J., Bochanski, J., Burgasser, A., Capak, P., Cruz, K., Hinz, P., Kartaltepe, J., Knox, R., Manohar, S., Masters, D., Morales-Calderon, M., Prato, L., Rodigas, T., Salvato, M., Schurr, S., Scoville, N., Simcoe, R., Stapelfeldt, K., Stern, D., Stock, N., Vacca, W., 2011, ApJS, 197, 19, The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)
    We present ground-based spectroscopic verification of 6 Y dwarfs (see also Cushing et al.), 89 T dwarfs, 8 L dwarfs, and 1 M dwarf identified by the Wide-field Infrared Survey Explorer (WISE). Eighty of these are cold brown dwarfs with spectral types >=T6, six of which have been announced earlier by Mainzer et al. and Burgasser et al. We present color-color and color-type diagrams showing the locus of M, L, T, and Y dwarfs in WISE color space. Near-infrared and, in a few cases, optical spectra are presented for these discoveries. Near-infrared classifications as late as early Y are presented and objects with peculiar spectra are discussed. Using these new discoveries, we are also able to extend the optical T dwarf classification scheme from T8 to T9. After deriving an absolute WISE 4.6 m (W2) magnitude versus spectral type relation, we estimate spectrophotometric distances to our discoveries. We also use available astrometric measurements to provide preliminary trigonometric parallaxes to four of our discoveries, which have types of L9 pec (red), T8, T9, and Y0; all of these lie within 10 pc of the Sun. The Y0 dwarf, WISE 1541-2250, is the closest at 2.8+1.3 -0.6 pc if this 2.8 pc value persists after continued monitoring, WISE 1541-2250 will become the seventh closest stellar system to the Sun. Another 10 objects, with types between T6 and >Y0, have spectrophotometric distance estimates also placing them within 10 pc. The closest of these, the T6 dwarf WISE 1506+7027, is believed to fall at a distance of ~4.9 pc. WISE multi-epoch positions supplemented with positional info primarily from the Spitzer/Infrared Array Camera allow us to calculate proper motions and tangential velocities for roughly one-half of the new discoveries. This work represents the first step by WISE to complete a full-sky, volume-limited census of late-T and Y dwarfs. Using early results from this census, we present preliminary, lower limits to the space density of these objects and discuss constraints on both the functional form of the mass function and the low-mass limit of star formation.
  5. Blomme, J., Sarro, L., O'Donovan, F., Debosscher, J., Brown, T., Lopez, M., Dubath, P., Rimoldini, L., Charbonneau, D., Dunham, E., Mandushev, G., Ciardi, D., De Ridder, J., Aerts, C., 2011, MNRAS, 418, 96, Improved methodology for the automated classification of periodic variable stars
    We present a novel automated methodology to detect and classify periodic variable stars in a large data base of photometric time series. The methods are based on multivariate Bayesian statistics and use a multistage approach. We applied our method to the ground-based data of the Trans-Atlantic Exoplanet Survey (TrES) Lyr1 field, which is also observed by the Kepler satellite, covering 26 000 stars. We found many eclipsing binaries as well as classical non-radial pulsators, such as slowly pulsating B stars, Doradus, Cephei and Scuti stars. Also a few classical radial pulsators were found.
  6. Adams, E., Lopez-Morales, M., Elliot, J., Seager, S., Osip, D., Holman, M., Winn, J., Hoyer, S., Rojo, P., 2011, ApJ, 741, 102, Twenty-one New Light Curves of OGLE-TR-56b: New System Parameters and Limits on Timing Variations
    Although OGLE-TR-56b was the second transiting exoplanet discovered, only one light curve, observed in 2006, has been published besides the discovery data. We present 21 light curves of 19 different transits observed between 2003 July and 2009 July with the Magellan Telescopes and Gemini South. The combined analysis of the new light curves confirms a slightly inflated planetary radius relative to model predictions, with Rp = 1.378 0.090 RJ . However, the values found for the transit duration, semimajor axis, and inclination values differ significantly from the previous result, likely due to systematic errors. The new semimajor axis and inclination, a = 0.01942 0.00015 AU and i = 73fdg72 0fdg18, are smaller than previously reported, while the total duration, T 14 = 7931 38 s, is 18 minutes longer. The transit midtimes have errors from 23 s to several minutes, and no evidence is seen for transit midtime or duration variations. Similarly, no change is seen in the orbital period, implying a nominal stellar tidal decay factor of Q * = 107, with a 3 lower limit of 105.7.

    This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  7. Mandushev, G., Quinn, S., Buchhave, L., Dunham, E., Rabus, M., Oetiker, B., Latham, D., Charbonneau, D., Brown, T., Belmonte, J., O'Donovan, F., 2011, ApJ, 741, 114, TrES-5: A Massive Jupiter-sized Planet Transiting a Cool G Dwarf
    We report the discovery of TrES-5, a massive hot Jupiter that transits the star GSC 03949-00967 every 1.48 days. From spectroscopy of the star we estimate a stellar effective temperature of T eff = 5171 36 K, and from high-precision B, R, and I photometry of the transit we constrain the ratio of the semimajor axis a and the stellar radius R sstarf to be a/R sstarf = 6.07 0.14. We compare these values to model stellar isochrones to obtain a stellar mass of M sstarf = 0.893 0.024 M . Based on this estimate and the photometric time series, we constrain the stellar radius to be R sstarf = 0.866 0.013 R and the planet radius to be R p = 1.209 0.021 R J. We model our radial-velocity data assuming a circular orbit and find a planetary mass of 1.778 0.063 M J. Our radial-velocity observations rule out line-bisector variations that would indicate a specious detection resulting from a blend of an eclipsing binary system. TrES-5 orbits one of the faintest stars with transiting planets found to date from the ground and demonstrates that precise photometry and followup spectroscopy are possible, albeit challenging, even for such faint stars.
  8. Hunter, D., Zahedy, F., Bowsher, E., Wilcots, E., Kepley, A., Gaal, V., 2011, AJ, 142, 173, Mapping the Extended H I Distribution of Three Dwarf Galaxies
    We present large field H I-line emission maps obtained with the single-dish Green Bank Telescope centered on the dwarf irregular galaxies Sextans A, NGC 2366, and WLM. We do not detect the extended skirts of emission associated with the galaxies that were reported from Effelsberg observations. The ratio of H I at 1019 atoms cm-2 to optical extents of these galaxies is instead 2-3, which is normal for this type of galaxy. There is no evidence for a truncation in the H I distribution >=1019 atoms cm-2.
  9. Lissauer, J., Ragozzine, D., Fabrycky, D., Steffen, J., Ford, E., Jenkins, J., Shporer, A., Holman, M., Rowe, J., Quintana, E., Batalha, N., Borucki, W., Bryson, S., Caldwell, D., Carter, J., Ciardi, D., Dunham, E., Fortney, J., Gautier, T., Howell, S., Koch, D., Latham, D., Marcy, G., Morehead, R., Sasselov, D., 2011, ApJS, 197, 8, Architecture and Dynamics of Kepler's Candidate Multiple Transiting Planet Systems
    About one-third of the ~1200 transiting planet candidates detected in the first four months of Kepler data are members of multiple candidate systems. There are 115 target stars with two candidate transiting planets, 45 with three, 8 with four, and 1 each with five and six. We characterize the dynamical properties of these candidate multi-planet systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean-motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. We find that virtually all candidate systems are stable, as tested by numerical integrations that assume a nominal mass-radius relationship. Several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Using the observed multiplicity frequencies, we find that a single population of planetary systems that matches the higher multiplicities underpredicts the number of singly transiting systems. We provide constraints on the true multiplicity and mutual inclination distribution of the multi-candidate systems, revealing a population of systems with multiple super-Earth-size and Neptune-size planets with low to moderate mutual inclinations.
  10. Fressin, F., Torres, G., Desert, J., Charbonneau, D., Batalha, N., Fortney, J., Rowe, J., Allen, C., Borucki, W., Brown, T., Bryson, S., Ciardi, D., Cochran, W., Deming, D., Dunham, E., Fabrycky, D., Gautier, T., Gilliland, R., Henze, C., Holman, M., Howell, S., Jenkins, J., Kinemuchi, K., Knutson, H., Koch, D., Latham, D., Lissauer, J., Marcy, G., Ragozzine, D., Sasselov, D., Still, M., Tenenbaum, P., Uddin, K., 2011, ApJS, 197, 5, Kepler-10 c: a 2.2 Earth Radius Transiting Planet in a Multiple System
    The Kepler mission has recently announced the discovery of Kepler-10 b, the smallest exoplanet discovered to date and the first rocky planet found by the spacecraft. A second, 45 day period transit-like signal present in the photometry from the first eight months of data could not be confirmed as being caused by a planet at the time of that announcement. Here we apply the light curve modeling technique known as BLENDER to explore the possibility that the signal might be due to an astrophysical false positive (blend). To aid in this analysis we report the observation of two transits with the Spitzer Space Telescope at 4.5 m. When combined, they yield a transit depth of 344 85 ppm that is consistent with the depth in the Kepler passband (376 9 ppm, ignoring limb darkening), which rules out blends with an eclipsing binary of a significantly different color than the target. Using these observations along with other constraints from high-resolution imaging and spectroscopy, we are able to exclude the vast majority of possible false positives. We assess the likelihood of the remaining blends, and arrive conservatively at a false alarm rate of 1.6 10-5 that is small enough to validate the candidate as a planet (designated Kepler-10 c) with a very high level of confidence. The radius of this object is measured to be Rp = 2.227+0.052 -0.057 R (in which the error includes the uncertainty in the stellar properties), but currently available radial-velocity measurements only place an upper limit on its mass of about 20 M . Kepler-10 c represents another example (with Kepler-9 d and Kepler-11 g) of statistical "validation" of a transiting exoplanet, as opposed to the usual "confirmation" that can take place when the Doppler signal is detected or transit timing variations are measured. It is anticipated that many of Kepler's smaller candidates will receive a similar treatment since dynamical confirmation may be difficult or impractical with the sensitivity of current instrumentation.
  11. Gilliland, R., Chaplin, W., Dunham, E., Argabright, V., Borucki, W., Basri, G., Bryson, S., Buzasi, D., Caldwell, D., Elsworth, Y., Jenkins, J., Koch, D., Kolodziejczak, J., Miglio, A., van Cleve, J., Walkowicz, L., Welsh, W., 2011, ApJS, 197, 6, Kepler Mission Stellar and Instrument Noise Properties
    Kepler mission results are rapidly contributing to fundamentally new discoveries in both the exoplanet and asteroseismology fields. The data returned from Kepler are unique in terms of the number of stars observed, precision of photometry for time series observations, and the temporal extent of high duty cycle observations. As the first mission to provide extensive time series measurements on thousands of stars over months to years at a level hitherto possible only for the Sun, the results from Kepler will vastly increase our knowledge of stellar variability for quiet solar-type stars. Here, we report on the stellar noise inferred on the timescale of a few hours of most interest for detection of exoplanets via transits. By design the data from moderately bright Kepler stars are expected to have roughly comparable levels of noise intrinsic to the stars and arising from a combination of fundamental limitations such as Poisson statistics and any instrument noise. The noise levels attained by Kepler on-orbit exceed by some 50% the target levels for solar-type, quiet stars. We provide a decomposition of observed noise for an ensemble of 12th magnitude stars arising from fundamental terms (Poisson and readout noise), added noise due to the instrument and that intrinsic to the stars. The largest factor in the modestly higher than anticipated noise follows from intrinsic stellar noise. We show that using stellar parameters from galactic stellar synthesis models, and projections to stellar rotation, activity, and hence noise levels reproduce the primary intrinsic stellar noise features.
  12. Ford, E., Rowe, J., Fabrycky, D., Carter, J., Holman, M., Lissauer, J., Ragozzine, D., Steffen, J., Batalha, N., Borucki, W., Bryson, S., Caldwell, D., Dunham, E., Gautier, T., Jenkins, J., Koch, D., Li, J., Lucas, P., Marcy, G., McCauliff, S., Mullally, F., Quintana, E., Still, M., Tenenbaum, P., Thompson, S., Twicken, J., 2011, ApJS, 197, 2, Transit Timing Observations from Kepler. I. Statistical Analysis of the First Four Months
    The architectures of multiple planet systems can provide valuable constraints on models of planet formation, including orbital migration, and excitation of orbital eccentricities and inclinations. NASA's Kepler mission has identified 1235 transiting planet candidates. The method of transit timing variations (TTVs) has already confirmed seven planets in two planetary systems. We perform a transit timing analysis of the Kepler planet candidates. We find that at least ~11% of planet candidates currently suitable for TTV analysis show evidence suggestive of TTVs, representing at least ~65 TTV candidates. In all cases, the time span of observations must increase for TTVs to provide strong constraints on planet masses and/or orbits, as expected based on N-body integrations of multiple transiting planet candidate systems (assuming circular and coplanar orbits). We find the fraction of planet candidates showing TTVs in this data set does not vary significantly with the number of transiting planet candidates per star, suggesting significant mutual inclinations and that many stars with a single transiting planet should host additional non-transiting planets. We anticipate that Kepler could confirm (or reject) at least ~12 systems with multiple transiting planet candidates via TTVs. Thus, TTVs will provide a powerful tool for confirming transiting planets and characterizing the orbital dynamics of low-mass planets. If Kepler observations were extended to at least seven years, then TTVs would provide much more precise constraints on the dynamics of systems with multiple transiting planets and would become sensitive to planets with orbital periods extending into the habitable zone of solar-type stars.
  13. Buchhave, L., Latham, D., Carter, J., Desert, J., Torres, G., Adams, E., Bryson, S., Charbonneau, D., Ciardi, D., Kulesa, C., Dupree, A., Fischer, D., Fressin, F., Gautier, T., Gilliland, R., Howell, S., Isaacson, H., Jenkins, J., Marcy, G., McCarthy, D., Rowe, J., Batalha, N., Borucki, W., Brown, T., Caldwell, D., Christiansen, J., Cochran, W., Deming, D., Dunham, E., Everett, M., Ford, E., Fortney, J., Geary, J., Girouard, F., Haas, M., Holman, M., Horch, E., Klaus, T., Knutson, H., Koch, D., Kolodziejczak, J., Lissauer, J., Machalek, P., Mullally, F., Still, M., Quinn, S., Seager, S., Thompson, S., Van Cleve, J., 2011, ApJS, 197, 3, Kepler-14b: A Massive Hot Jupiter Transiting an F Star in a Close Visual Binary
    We present the discovery of a hot Jupiter transiting an F star in a close visual (0farcs3 sky projected angular separation) binary system. The dilution of the host star's light by the nearly equal magnitude stellar companion (~0.5 mag fainter) significantly affects the derived planetary parameters, and if left uncorrected, leads to an underestimate of the radius and mass of the planet by 10% and 60%, respectively. Other published exoplanets, which have not been observed with high-resolution imaging, could similarly have unresolved stellar companions and thus have incorrectly derived planetary parameters. Kepler-14b (KOI-98) has a period of P = 6.790 days and, correcting for the dilution, has a mass of Mp = 8.40+0.35 - 0.34 M J and a radius of Rp = 1.136+0.073 - 0.054 R J, yielding a mean density of p = 7.1 1.1 g cm-3.
  14. Porter, S., Grundy, W., 2011, epsc, 2011, 178, KCTF Evolution of Trans-Neptunian Binaries
    Recent observational surveys of Trans-Neptunian Binary (TNB) systems have dramatically increased the number of known mutual orbits. Kozai Cycle Tidal Friction (KCTF) simulations of synthetic binary systems shows that tidal dissipation in these systems can totally reshape their orbits. Specifically, solar torques should have dramatically accelerated the tidal decay and circularization of primordial (or recently excited) TNBs. As a result, an initially random distribution of TNBs will evolve to three distinct populations: extremely tight systems, very low inclination systems, and long-term Kozai oscillators. The tight systems account for approximately one third of evolved systems, while one third to one half are coplanar. These populations appear for a range of TNO physical properties, with stronger gravitational quadrapole minimizing variation due to different physical tidal properties.
  15. Foote, E., Paige, D., Shepard, M., Johnson, J., Grundy, W., Biggar, S., Greenhagen, B., Allen, C., 2011, epsc, 2011, 329, The Bidirectional Reflectance of Apollo Lunar Soils
    We have compared laboratory solar bidirectional reflectance measurements of a diverse set of Apollo soil samples with Lunar Reconnaissance Orbiter (LRO) Diviner orbital albedo measurements at the Apollo 11 and 16 landing sites. Preliminary results show good agreement between the laboratory and orbital measurements at low phase angles. We expect reasonable agreement between the Apollo 12, 15, and 17 landing sites once we complete those measurements.
  16. French, L., Stephens, R., Lederer, S., Wasserman, L., Coley, D., Rohl, D., La Rocca, D., 2011, epsc, 2011, 351, Preliminary Results from a Rotation Survey of Jovian Trojan Asteroids
    Lightcurve results are presented for 16 Jupiter Trojan asteroids from observations obtained at Cerro Tololo Interamerican Observatory, GMARS Observatory, and Lowell Observatory from October 2009 to January 2011.
  17. Protopapa, S., Boehnhardt, H., Barrera, L., Grundy, W., Cruikshank, D., Sunshine, J., Feaga, L., A'Hearn, M., 2011, epsc, 2011, 512, Longitudinal and temporal variability of Pluto
    In particular, we present low dispersion L band spectroscopy together with high dispersion spectroscopy in H and K bands of Pluto acquired with the NACO instrument at the ESO VLT on 27 June 2008. The nature and properties of the compounds present on the surface of Pluto are investigated by applying a Hapke radiative transfer model to the measured spectra. The 2008 observations are compared with 2005 measurements obtained with the same instrument and spectroscopic mode, covering similar sub-earth longitudes. A systematic study of Pluto's surface composition is presented in order to characterize the spatial and temporal distribution of Pluto's surface ices. The spectra of Pluto obtained at different sub-earth longitudes do not show any significant difference in the wavelength range between 2.9 and 3.7m. No changes in the ratio between pure and diluted methane ice are observed from 2005 to 2008, indicating that Pluto's resurfacing process has slowed down or stopped.
  18. Knight, M., Schleicher, D., 2011, epsc, 2011, 655, Photometry and Imaging of Comet 103P/Hartley 2 from Lowell Observatory
    We will discuss some results based on our imaging and photometric observations of Comet 103P/Hartley 2. Photometry was obtained during the 1991, 1997, and 2010 apparitions. These data reveal a strong secular decrease in production rates from 1991 to 2010 and a strong pre-/post-perihelion asymmetry in 2010. Imaging was obtained over 39 nights from 2010 July through 2011 January and analyses of the data are ongoing. We will discuss the CN coma morphology and make intercomparisons between gas species (CN, OH, C2, and C3), investigate the appearance and behavior of a possible dust jet, and refine the pole solution by combining the published results of multiple authors.
  19. Fuentes, C., Trilling, D., Knight, M., 2011, epsc, 2011, 682, The most dangerous IEOs in STEREO
    IEOs (inner Earth objects or interior Earth objects) are potentially the most dangerous near Earth small body population. Their study is complicated by the fact the population spends all of its time inside the orbit of the Earth, giving ground-based telescopes a small window to observe them. We introduce STEREO (Solar TErrestrial RElations Observatory) and its 5 years of archival data as our best chance of studying the IEO population and discovering possible impactor threats to Earth. We show that in our current search for IEOs in STEREO data we are capable of detecting and characterizing the orbits of 10-100 potentially dangerous IEOs. The number of expected detections by STEREO is based on the current number of known IEOs which is heavily biased by the 8 objects discovered so far [4]. STEREO is sensitive to IEOs that are not visible from the Earth and hence samples a part of the IEO population that has not been discovered yet.
  20. Noll, K., Grundy, W., Benecchi, S., Levison, H., 2011, epsc, 2011, 1029, The Relative Sizes of Transneptunian Binaries: Evidence for Different Populations from a Homogeneous Data Set
    A unique feature of Transneptunian Objects is the prevalence of binaries made up of comparably-sized components. Nearly-equal-brightness binaries are especially common in the low inclination Cold Classicals where all companions differ by mag < 1.5. With the assumption of equal albedos, this translates to secondaries with radii half that of the primary or greater. By contrast, members of the dynamically hot population, Hot Classical, Resonant, and Scattered Disk, have a larger range of secondary sizes. Detection of satellites with magnitude differences of mag > 5, corresponding to secondary radii less than 10% of the primary, are rare. This is explained, in part, by detection biases that limit the detectability of faint secondaries and secondaries that are close to their primary. However, the lack of companions with mag > 1.5 at separations of more than 0.1 arcsec (2900 km at 40 AU), independent of dynamical classification, is strongly constrained with the current data. This limit constrains the overall population of such secondaries.
  21. Grundy, W., Benecchi, S., Buie, M., Noll, K., Porter, S., Roe, H., Stansberry, J., Trujillo, C., 2011, epsc, 2011, 1078, A New NOAO Survey Program: Mutual Orbits and Masses of Kuiper Belt Binaries
    We will report progress from our multi-year campaign to determine the orbits and masses of transneptunian binaries (TNBs). Binary systems are abundant in the Kuiper belt, and especially among the "Cold Classical" disk of objects on low-eccentricity, lowinclination, non-resonant orbits about the Sun [1]. These binaries offer an opportunity to learn the masses and densities of an intriguing population of small, distant objects. Additionally, the statistics of their mutual orbital parameters offer clues to conditions where they formed in the protoplanetary nebula, as well as to subsequent dynamical evolution of the outer solar system. Historically, NASA/ESA's Hubble Space Telescope (HST) has been the premier facility for spatially resolving the components of TNBs, benefiting from its exceptionally stable optics and from diffraction- limited imaging unimpeded by the Earth's atmosphere. More recently, laser guide star adaptive optics (LGS AO) technology has enabled large groundbased telescopes to begin contributing valuable data as well [2]. LGS AO observations of faint TNBs (the components of which have typical V magnitudes ~24th) are only feasible when the target passes near an appulse star suitable for use as a tip-tilt correction reference. We have been using LGS AO data from Keck in combination with HST data to constrain TNB orbits [e.g., 3]. In 2011 we began a new 3-year NOAO Survey program to use LGS AO on the 8 m Gemini North telescope. We will discuss how Gemini and other telescopes complement one another, show examples of data from Gemini, Keck, and HST, and describe how we are using these facilities to improve orbital knowledge for as many of the tighter TNBs as we can. Optimal scheduling techniques enable us to make the most efficient possible use of the very limited availability of time on telescopes capable of resolving these objects [4]. Our progress is documented online at http://www.lowell.edu/~grundy/tnbs. We will discuss systems of particular interest such as those likely to undergo mutual events in the near future. These include 2003 QW111 (events probably beginning in a few years) and 79360 1997 CS29 (events probably happening right now). Also of interest are systems for which sizes can be independently determined from thermal or other observations. For these systems, the dynamical masses from binary orbits enable computation of bulk densities. We will also explore statistical patterns beginning to emerge from the growing ensemble of known TNB orbits. Observed distributions of orbital characteristics, including inclinations, eccentricities, and separations have important implications for formation scenarios as well as subsequent evolution [5], although accounting for observational biases remains an open issue. For instance, there appears to be a shortage of loose binaries among TNOs on excited heliocentric orbits. While there seems to be an excess of prograde systems among the tighter binaries, there is little evidence for preferentially low inclinations.
  22. Person, M., Dunham, E., Bida, T., Bosh, A., Collins, P., Levine, S., Mandushev, G., Taylor, B., Tilleman, T., Zangari, A., Zoonemat Kermani, S., 2011, epsc, 2011, 1374, First Small-Body Occultation Attempts from the Stratospheric Observatory for Infrared Astronomy
    Here we report the first attempts to observe a stellar occultation from the Stratospheric Observatory for Infrared Astronomy. We predicted and will attempt to observe the stellar occultations by Pluto and Charon on 23 June 2011 UT and by Pluto and Hydra on 27 June 2011 UT. We shall provide details on the predictions, preparation, and any successful observations and initial results and implications for the Pluto system.
  23. Zangari, A., Dunham, E., Mandushev, G., Person, M., Collins, P., Bida, T., Taylor, B., Zoonematkermani, S., 2011, epsc, 2011, 1378, Laboratory precision photometry test results for the High-speed Imaging Photometer for Occultations (HIPO)
    We present the results of several laboratory precision photometry tests using the High-speed Imaging Photometer for Occultations (HIPO), one of seven first generation instruments of the Stratospheric Observatory For Infrared Astronomy (SOFIA). Using artificial stars illuminated by an integrating sphere, we have tested the stability of the photometry in the laboratory against variations in chip temperature, controller temperature, and power supply temperature. We find that changes in the controller temperature and the chip temperature correlate with millimag-level changes in differential photometry and sub-pixel changes in the centroid location of the artificial stars. We find that data can be averaged for up to 10 minutes and 0.1 millimag during times of temperature fluctuations if a single amplifier is used to take data without effecting the results. We make operating recommendations based on the test results and discuss the suitability of HIPO for research beyond occultations, such as exoplanet transits.
  24. Bender, C., Carr, J., Blake, G., Barman, T., Johnson, J., Lockwood, A., 2011, epsc, 2011, 1393, Direct Spectroscopic Characterization of Hot Exoplanet Atmospheres
    We will present current results from our program using high-contrast, high-resolution spectroscopy to directly detect and characterize the atmospheres of short period, hot exoplanets. Our observations target the thermal emission of these planets, and are sensitive to molecules in their atmospheres. We treat these planet+star systems as spectroscopic binaries, and measure the radial velocity of the planet with orbital phase and the planet/star flux ratio at specific bandpasses. These quantities yield a planet's true mass and probe the physics and chemistry of its atmosphere. This technique can directly characterize the large population of non-transiting planets that other surveys are insensitive to.
  25. Roe, H., Greathouse, T., Tokunaga, A., 2011, epsc, 2011, 1398, Update on the TEXES Titan Mid-Infrared Spectral Survey
    At this meeting we will present the current status of the survey, including results on allene (CH2CCH2). We have tentatively identified several of the 10 subbands of allene amongst the strong emission lines of ethane's 12 822 cm-1 band. The observed spectrum of the 845 cm-1 subband are shown in Figure 1. Although often searched for, allene has not previously been detected in Titan's atmosphere. We discuss the challenges of identifying and measuring the abundance of allene when line lists and strengths are often in significant disagreement. In the case of allene a commonly used line list3 predicts significantly stronger emission for the same atmospheric abundance than what is predicted using absorption coefficient spectra empirically derived from cold laboratory spectroscopy. The lack of good line lists and/or high-resolution cold laboratory spectra is a significant obstacle to identifying the many as-yet-unidentified emission lines in the survey's spectra.
  26. Oszkiewicz, D., Bowell, E., Wasserman, L., Muinonen, K., Penttila, A., Pieniluoma, T., Trilling, D., Thomas, C., 2011, epsc, 2011, 1539, Information on asteroid taxonomy contained in phase curves
    We report our findings on asteroid phase curves based on processing large amount of photometric data contained in the Lowell Observatory photometric database [1, 2]. We fitted phase curves [3] to about half a million asteroids contained in the database. We found homogeneity in G12 slope parameters [1] in asteroid families and correlation of G12 with asteroid taxonomic complexes [2]. We predict taxonomic complex preponderance in asteroid families based on G12 slope parameters and compare our results with those available in the literature.
  27. Bowell, E., Oszkiewicz, D., Wasserman, L., Muinonen, K., Penttila, A., Trilling, D., 2011, epsc, 2011, 1549, Asteroid spin-axis longitudes from the Lowell observatory database
    Using the Lowell Observatory photometric database, we analyze the variation of reduced magnitudes with ecliptic longitude, thereby estimating spin-axis longitudes for hundred of thousands of asteroids. Hitherto, spin-axis longitude estimates have been made for fewer then two hundred asteroids. We investigate longitude distributions in different dynamical groups and longitude preferences in asteroid families. We show that asteroid spin-axis longitudes are not isotropically distributed, as has been suggested by some theoretical studies. For the main belt as a whole, we find a marked depletion of spin-axis longitudes near 140 and excesses near 30 and 90. For Jupiter Trojans there is preponderance of spin axes near 100. We describe longitude distributions for asteroid families.
  28. Bida, T., Killen, R., 2011, epsc, 2011, 1621, Observations of Al, Fe, and Ca+ in Mercury's exosphere
    We report 5- tangent column detections of Al and Fe, and strict 3- tangent column upper limits for Ca+ in Mercury's exosphere obtained using the HIRES spectrometer on the Keck I telescope. These are the first direct detections of Al and Fe in Mercury's exosphere. Our Ca+ observation is consistent with that reported by the The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft [1].
  29. von Braun, K., Boyajian, T., Turner, N., Farrington, C., Goldfinger, P., Kane, S., Ciardi, D., van Belle, G., ten Brummelaar, T., Lopez-Morales, M., McAlister, H., Schaefer, G., Henry, T., Ridgway, S., White, R., Sturmann, L., Sturmann, J., 2011, epsc, 2011, 1622, Interferometric Studies of Exoplanet Hosting Stars
    Planetary characterization is playing an increasingly important role in exoplanet research. A frequently overlooked aspect in the calculation of physical quantities of these planets is that they are actually functions of astrophysical parameters of the host stars, such as stellar luminosity or diameter. The value of "understanding the parent stars" cannot be overstated in the realm of assessing the radii of transiting planets, the potential of harboring liquid water on exoplanets (habitable zone), the planetary equilibrium temperatures, etc. We use long-baseline interferometry to provide directly determined stellar astrophysical parameters of exoplanet host stars with the aim of characterizing their planet population. In this presentation, we show the results of our studies of the multiplanet systems GJ 581, GJ 876, and 55 Cancri with planets in or near the respective habitable zones, and of GJ 436 with a transiting hot Neptune.
  30. Buie, M., Tholen, D., Wasserman, L., Sicardy, B., Young, L., Young, E., Ryan, W., Ryan, E., Walsh, K., Widemann, T., Vachier, F., Beisker, W., Hall, T., Dire, J., Erickson, C., Nance, C., Person, M., 2011, epsc, 2011, 1715, Hydra stellar occulatation of 2011 June 27
    We will present details regarding the deployment strategies, prediction efforts, and final results of a stellar occultation by Pluto's outermost satellite, Hydra, that is predicted to occur on 2011 June 27.
  31. Roe, H., Dunham, E., Bida, T., Hall, J., Degroff, W., 2011, epsc, 2011, 1823, A near-infrared spectrograph for the Discovery Channel Telescope
    Lowell Observatory is constructing the Discovery Channel Telescope (DCT) at Happy Jack, Arizona, approximately an hour from Lowell's main campus in Flagstaff, Arizona. The DCT is a 4.3-m optical/ infrared telescope. Construction of the telescope is complete and First Light of the DCT is planned for 2012Q2. In its initial configuration instruments will be co-mounted on a rotatable/selectable cube at the Cassegrain focus. Motorized deployable fold mirrors enable rapid switching amongst instruments. In the future the Nasmyth foci will be available for larger instruments as well. The first generation of instruments on DCT include: the Large Monolithic Imager (LMI), the Near-Infrared High-Throughput Spectrograph (NIHTS, pronounced "nights"), and the DeVeny optical spectrograph. The LMI contains a single large 6.1x6.1 K detector with a 12.5 arcmin2 FOV. NIHTS is a low resolution efficient near-infrared spectrograph and is the subject of this presentation. The DeVeny is Lowell's existing optical spectrograph with resolutions available between 500 and 4000. NIHTS is a low-resolution high-throughput infrared spectrograph covering 0.9-2.4 m in a single fixed spectral setting at a resolution of 100. For simplicity and replicability NIHTS contains no moving parts. The science detector is a 10242 HAWAII-1 array. The fixed slit plate features an 80" long slit with several different slit widths (2,3,4 and 12 pixels) available along its length. The widest slit width is designed to allow accurate flux calibration, while the 3 and 4-pixel slits are closely matched to typical seeing at the DCT site (0.86" mean). Different resolutions will be rapidly selectable by dithering the telescope, and a typical observation is anticipated to involve a sequence of dithers both at the desired resolution and at SED resolution for calibration purposes. Offset guiding and wavefront sensing to control the active optics of the primary mirror are provided by the facility via deployable probes in the instrument cube. Target acquisition and slit-guiding is possible in the optical with the LMI or in the near-infrared with an In- GaAs slit-viewing camera that is part of NIHTS. Because the fold mirror to NIHTS is a dichroic, simultaneous optical imaging with LMI and near-infrared spectroscopy with NIHTS is enabled. NASA funded the construction of NIHTS as part of a larger project, the Kuiper Spectral Survey (KSS), and will be available to all users of the DCT.
  32. Zuluaga, C., Person, M., Bosh, A., Levine, S., Gulbis, A., Zangari, A., Pasachoff, J., Babcock, B., Pandey, S., Amrhein, D., Sallum, S., Dunham, E., Tholen, D., Collins, P., Bida, T., Taylor, B., Lucas, R., Kakkala, M., Ciotti, J., Plunkett, S., Hiraoka, N., Best, W., Pilger, E., Miceli, M., Springmann, A., Hicks, M., Thackeray, B., Emery, J., Rapoport, S., Ritchie, I., Pearson, M., Mattingly, A., Brimacombe, J., Gault, D., Jones, R., Nolthenius, R., Broughton, J., Barry, T., 2011, epsc, 2011, 1866, Measured Pluto-Charon Offset from the Stellar Occultations of 23 June 2011
    We report on our Charon results from the double occultation observed on 23 June 2011 [1,2,3]. Our group successfully observed the occultation of the same star, 2UCAC 24677089, by Pluto and Charon shown in Figure 1. Charon occulted the star first, and its shadow was offset from that of Pluto by about 1200 km to the north. Thus, observers on the big island of Hawaii and along most of Baja were in the double-occultation zone, where occultations by both Pluto and Charon could be observed. Observers were located around the globe for this event. In Table 1 we list the sites and instruments used. Using GPStriggered instrument MORIS [4] at the NASA Infrared Telescope Facility (IRTF), we were able to record both occultations within approximately 11 minutes of each other. We obtained Charon-only light curves at an additional three sites. Observations at Leeward Community College on Oahu were made using a GPS-triggered Portable Occultation, Eclipse, and Transit System (POETS [5]). Observers at Table Mountain Observatory (CA) used a GPS-triggered Portable Instrument for Capturing Occultations (PICO [6]). Data were acquired at the U. S. Naval Observatory - Flagstaff Station (AZ) with the USNO Array Camera, an array of six 2k by 4k chips by e2v. We will analyze these data to solve for the shape and size of Charon as well as to how its position relative to Pluto compares to the JPL PLU017 ephemeris.
  33. Raiteri, C., Villata, M., Aller, M., Gurwell, M., Kurtanidze, O., Lahteenmaki, A., Larionov, V., Romano, P., Vercellone, S., Agudo, I., Aller, H., Arkharov, A., Bach, U., Benitez, E., Berdyugin, A., Blinov, D., Borisova, E., Bottcher, M., Bravo Calle, O., Buemi, C., Calcidese, P., Carosati, D., Casas, R., Chen, W., Efimova, N., Gomez, J., Gusbar, C., Hawkins, K., Heidt, J., Hiriart, D., Hsiao, H., Jordan, B., Jorstad, S., Joshi, M., Kimeridze, G., Koptelova, E., Konstantinova, T., Kopatskaya, E., Kurtanidze, S., Larionova, E., Larionova, L., Leto, P., Li, Y., Ligustri, R., Lindfors, E., Lister, M., Marscher, A., Molina, S., Morozova, D., Nieppola, E., Nikolashvili, M., Nilsson, K., Palma, N., Pasanen, M., Reinthal, R., Roberts, V., Ros, J., Roustazadeh, P., Sadun, A., Sakamoto, T., Schwartz, R., Sigua, L., Sillanpaa, A., Takalo, L., Tammi, J., Taylor, B., Tornikoski, M., Trigilio, C., Troitsky, I., Umana, G., Volvach, A., Yuldasheva, T., 2011, A&A, 534, A87, The long-lasting activity of 3C 454.3. GASP-WEBT and satellite observations in 2008-2010
    Context. The blazar 3C 454.3 is one of the most active sources from the radio to the -ray frequencies observed in the past few years.
    Aims: We present multiwavelength observations of this source from April 2008 to March 2010. The radio to optical data are mostly from the GASP-WEBT, UV and X-ray data from Swift, and -ray data from the AGILE and Fermi satellites. The aim is to understand the connection among emissions at different frequencies and to derive information on the emitting jet.
    Methods: Light curves in 18 bands were carefully assembled to study flux variability correlations. We improved the calibration of optical-UV data from the UVOT and OM instruments and estimated the Ly flux to disentangle the contributions from different components in this spectral region.
    Results: The observations reveal prominent variability above 8 GHz. In the optical-UV band, the variability amplitude decreases with increasing frequency due to a steadier radiation from both a broad line region and an accretion disc. The optical flux reaches nearly the same levels in the 2008-2009 and 2009-2010 observing seasons; the mm one shows similar behaviour, whereas the and X-ray flux levels rise in the second period. Two prominent -ray flares in mid 2008 and late 2009 show a double-peaked structure, with a variable /optical flux ratio. The X-ray flux variations seem to follow the -ray and optical ones by about 0.5 and 1 d, respectively.
    Conclusions: We interpret the multifrequency behaviour in terms of an inhomogeneous curved jet, where synchrotron radiation of increasing wavelength is produced in progressively outer and wider jet regions, which can change their orientation in time. In particular, we assume that the long-term variability is due to this geometrical effect. By combining the optical and mm light curves to fit the and X-ray ones, we find that the (X-ray) emission may be explained by inverse-Comptonisation of synchrotron optical (IR) photons by their parent relativistic electrons (SSC process). A slight, variable misalignment between the synchrotron and Comptonisation zones would explain the increased and X-ray flux levels in 2009-2010, as well as the change in the /optical flux ratio during the outbursts peaks. The time delays of the X-ray flux changes after the , and optical ones are consistent with the proposed scenario.

    The radio-to-optical data presented in this paper are stored in the GASP-WEBT archive; for questions regarding their availability, please contact the WEBT President Massimo Villata (villata@oato.inaf.it).Table 3 is available in electronic form at http://www.aanda.org

  34. Hunter, D., Elmegreen, B., Oh, S., Anderson, E., Nordgren, T., Massey, P., Wilsey, N., Riabokin, M., 2011, AJ, 142, 121, The Outer Disks of Dwarf Irregular Galaxies
    In order to explore the properties of extreme outer stellar disks, we obtained ultra-deep V and GALEX ultraviolet (UV) images of four dwarf irregular galaxies and one blue compact dwarf galaxy, and ultra-deep B images of three of these. Our V-band surface photometry extends to 29.5 mag arcsec-2. We convert the FUV and V-band photometry, along with H photometry obtained in a larger survey, into radial star formation rate profiles that are sensitive to timescales from 10 Myr to the lifetime of the galaxy. We also obtained H I-line emission data and compare the stellar distributions, surface brightness profiles, and star formation rate profiles to H I-line emission maps, gas surface density profiles, and gas kinematics. Our data lead us to two general observations. First, the exponential disks in these irregular galaxies are extraordinarily regular. We observe that the stellar disks continue to decline exponentially as far as our measurements extend. In spite of lumpiness in the distribution of young stars and H I distributions and kinematics that have significant unordered motions, sporadic processes that have built the disksstar formation, radial movement of stars, and perhaps even perturbations from the outsidehave, nevertheless, conspired to produce standard disk profiles. Second, there is a remarkable continuity of star formation throughout these disks over time. In four out of five of our galaxies the star formation rate in the outer disk measured from the FUV tracks that determined from the V-band, to within factors of five, requiring star formation at a fairly steady rate over the galaxy's lifetime. Yet, the H I surface density profiles generally decline with radius more shallowly than the stellar light, and the gas is marginally gravitationally stable against collapse into clouds. Outer stellar disks are challenging our concepts of star formation and disk growth and provide a critical environment in which to understand processes that mold galaxy disks.
  35. Galicher, R., Marois, C., Macintosh, B., Barman, T., Konopacky, Q., 2011, ApJL, 739, L41, M-band Imaging of the HR 8799 Planetary System Using an Innovative LOCI-based Background Subtraction Technique
    Multi-wavelength observations/spectroscopy of exoplanetary atmospheres are the basis of the emerging exciting field of comparative exoplanetology. The HR 8799 planetary system is an ideal laboratory to study our current knowledge gap between massive field brown dwarfs and the cold 5 Gyr old solar system planets. The HR 8799 planets have so far been imaged at J- to L-band, with only upper limits available at M-band. We present here deep high-contrast Keck II adaptive optics M-band observations that show the imaging detection of three of the four currently known HR 8799 planets. Such detections were made possible due to the development of an innovative LOCI-based background subtraction scheme that is three times more efficient than a classical median background subtraction for Keck II AO data, representing a gain in telescope time of up to a factor of nine. These M-band detections extend the broadband photometric coverage out to ~5 m and provide access to the strong CO fundamental absorption band at 4.5 m. The new M-band photometry shows that the HR 8799 planets are located near the L/T-type dwarf transition, similar to what was found by other studies. We also confirm that the best atmospheric fits are consistent with low surface gravity, dusty, and non-equilibrium CO/CH4 chemistry models.
  36. Doyle, L., Carter, J., Fabrycky, D., Slawson, R., Howell, S., Winn, J., Orosz, J., Prsa, A., Welsh, W., Quinn, S., Latham, D., Torres, G., Buchhave, L., Marcy, G., Fortney, J., Shporer, A., Ford, E., Lissauer, J., Ragozzine, D., Rucker, M., Batalha, N., Jenkins, J., Borucki, W., Koch, D., Middour, C., Hall, J., McCauliff, S., Fanelli, M., Quintana, E., Holman, M., Caldwell, D., Still, M., Stefanik, R., Brown, W., Esquerdo, G., Tang, S., Furesz, G., Geary, J., Berlind, P., Calkins, M., Short, D., Steffen, J., Sasselov, D., Dunham, E., Cochran, W., Boss, A., Haas, M., Buzasi, D., Fischer, D., 2011, Sci, 333, 1602, Kepler-16: A Transiting Circumbinary Planet
    We report the detection of a planet whose orbit surrounds a pair of low-mass stars. Data from the Kepler spacecraft reveal transits of the planet across both stars, in addition to the mutual eclipses of the stars, giving precise constraints on the absolute dimensions of all three bodies. The planet is comparable to Saturn in mass and size and is on a nearly circular 229-day orbit around its two parent stars. The eclipsing stars are 20 and 69% as massive as the Sun and have an eccentric 41-day orbit. The motions of all three bodies are confined to within 0.5 of a single plane, suggesting that the planet formed within a circumbinary disk.
  37. Anderson, D., Smith, A., Lanotte, A., Barman, T., Collier Cameron, A., Campo, C., Gillon, M., Harrington, J., Hellier, C., Maxted, P., Queloz, D., Triaud, A., Wheatley, P., 2011, MNRAS, 416, 2108, Thermal emission at 4.5 and 8 m of WASP-17b, an extremely large planet in a slightly eccentric orbit
    We report the detection of thermal emission at 4.5 and 8 m from the planet WASP-17b. We used Spitzer to measure the system brightness at each wavelength during two occultations of the planet by its host star. By combining the resulting light curves with existing transit light curves and radial-velocity measurements in a simultaneous analysis, we find the radius of WASP-17b to be 2.0RJup, which is 0.2RJup larger than any other known planet and 0.7RJup larger than predicted by the standard cooling theory of irradiated gas giant planets. We find the retrograde orbit of WASP-17b to be slightly eccentric, with 0.0012 < e < 0.070 (3). Such a low eccentricity suggests that, under current models, tidal heating alone could not have bloated the planet to its current size, so the radius of WASP-17b is currently unexplained. From the measured planet-star flux-density ratios we infer 4.5 and 8 m brightness temperatures of 1881 50 and 1580 150 K, respectively, consistent with a low-albedo planet that efficiently redistributes heat from its day side to its night side.
  38. Dalle Ore, C., Fulchignoni, M., Cruikshank, D., Barucci, M., Brunetto, R., Campins, H., de Bergh, C., Debes, J., Dotto, E., Emery, J., Grundy, W., Jones, A., Mennella, V., Orthous-Daunay, F., Owen, T., Pascucci, I., Pendleton, Y., Pinilla-Alonso, N., Quirico, E., Strazzulla, G., 2011, A&A, 533, A98, Organic materials in planetary and protoplanetary systems: nature or nurture?

    Aims: The objective of this work is to summarize the discussion of a workshop aimed at investigating the properties, origins, and evolution of the materials that are responsible for the red coloration of the small objects in the outer parts of the solar system. Because of limitations or inconsistencies in the observations and, until recently, the limited availability of laboratory data, there are still many questions on the subject. Our goal is to approach two of the main questions in a systematic way: - Is coloring an original signature of materials that are presolar in origin ("nature") or stems from post-formational chemical alteration, or weathering ("nurture")? - What is the chemical signature of the material that causes spectra to be sloped towards the red in the visible? We examine evidence available both from the laboratory and from observations sampling different parts of the solar system and circumstellar regions (disks).
    Methods: We present a compilation of brief summaries gathered during the workshop and describe the evidence towards a primordial vs. evolutionary origin for the material that reddens the small objects in the outer parts of our, as well as in other, planetary systems. We proceed by first summarizing laboratory results followed by observational data collected at various distances from the Sun.
    Results: While laboratory experiments show clear evidence of irradiation effects, particularly from ion bombardment, the first obstacle often resides in the ability to unequivocally identify the organic material in the observations. The lack of extended spectral data of good quality and resolution is at the base of this problem. Furthermore, that both mechanisms, weathering and presolar, act on the icy materials in a spectroscopically indistinguishable way makes our goal of defining the impact of each mechanism challenging.
    Conclusions: Through a review of some of the workshop presentations and discussions, encompassing laboratory experiments as well as observational data, we infer that both "nature" and "nurture" are instrumental in the coloration of small objects in the outer parts
  39. Heesen, V., Rau, U., Rupen, M., Brinks, E., Hunter, D., 2011, ApJL, 739, L23, Deep Radio Continuum Imaging of the Dwarf Irregular Galaxy IC 10: Tracing Star Formation and Magnetic Fields
    We exploit the vastly increased sensitivity of the Expanded Very Large Array to study the radio continuum and polarization properties of the post-starburst, dwarf irregular galaxy IC 10 at 6 cm, at a linear resolution of ~50 pc. We find close agreement between radio continuum and H emission, from the brightest H II regions to the weaker emission in the disk. A quantitative analysis shows a strictly linear correlation, where the thermal component contributes 50% to the total radio emission, the remainder being due to a non-thermal component with a surprisingly steep radio spectral index of between -0.7 and -1.0 suggesting substantial radiation losses of the cosmic-ray electrons. We confirm and clearly resolve polarized emission at the 10%-20% level associated with a non-thermal superbubble, where the ordered magnetic field is possibly enhanced due to the compression of the expanding bubble. A fraction of the cosmic-ray electrons has likely escaped because the measured radio emission is a factor of three lower than what is suggested by the H-inferred star formation rate.
  40. Bianchi, L., Kang, Y., Efremova, B., Thilker, D., Hodge, P., Massey, P., Olsen, K., 2011, Ap&SS, 335, 249, Young stellar populations in the local group: an HST and GALEX comprehensive study
    The study of the stellar constituents of star-forming sites in a wide variety of conditions yields the key to interpreting wide-field UV-optical imaging of extended nearby galaxies, and of distant galaxies. We obtained six-band imaging (from far-UV to I) with HST-WFPC2 of 67 sites of recent star formation in eight Local Group galaxies. HST pointings were selected from GALEX wide-field FUV imaging, which traces the young stellar populations. The HST observations were optimized to characterize the hottest, most massive stars in these regions. From the HST photometry, analyzed with stellar model colors, we derived the physical parameters of the massive stars in each field, and of the extinction by interstellar dust. The HST results are used to interpret GALEX UV measurements of SF across the entire galaxies. Our comprehensive photometric study at HST resolution (sub-pc scale in these galaxies) also provides an ideal selection of targets for follow-up spectroscopy with large ground-based telescopes, and in the UV with HST- or WSO-class telescopes, to clarify the influence of metallicity on the properties and the evolution of massive stars.
  41. Simpson, C., Hunter, D., Nordgren, T., Brinks, E., Elmegreen, B., Ashley, T., Lynds, R., McIntyre, V., O'Neil, E., Ostlin, G., Westpfahl, D., Wilcots, E., 2011, AJ, 142, 82, VII Zw 403: H I Structure in a Blue Compact Dwarf Galaxy
    We present optical (UBVJ), ultraviolet (FUV, NUV), and high-resolution atomic hydrogen (H I) observations of the nearby blue compact dwarf (BCD), VII Zw 403. We find that VII Zw 403 has a relatively high H I mass-to-light ratio for a BCD. The rotation velocity is nominally 10-15 km s-1, but rises to ~20 km s-1 after correction for the ~8-10 km s-1 random motions present in the gas. The velocity field is complex, including a variation in the position angle of the major axis going from the northeast to the southwest parts of the galaxy. Our high-resolution H I maps reveal structure in the central gas, including a large, low-density H I depression or hole between the southern and northern halves of the galaxy, coincident with an unresolved X-ray source. Although interactions have been proposed as the triggering mechanism for the vigorous star formation occurring in BCDs, VII Zw 403 does not seem to have been tidally triggered by an external interaction, as we have found no nearby possible perturbers. It also does not appear to fall in the set of galaxies that exhibit a strong central mass density concentration, as its optical scale length is large in comparison to similar systems. However, there are some features that are compatible with an accretion event: optical/H I axis misalignment, a change in position angle of the kinematic axis, and a complex velocity field.
  42. Sanchez-Lavega, A., Orton, G., Hueso, R., Perez-Hoyos, S., Fletcher, L., Garcia-Melendo, E., Gomez-Forrellad, J., de Pater, I., Wong, M., Hammel, H., Yanamandra-Fisher, P., Simon-Miller, A., Barrado-Izagirre, N., Marchis, F., Mousis, O., Ortiz, J., Garcia-Rojas, J., Cecconi, M., Clarke, J., Noll, K., Pedraz, S., Wesley, A., Kalas, P., McConnell, N., Golisch, W., Griep, D., Sears, P., Volquardsen, E., Reddy, V., Shara, M., Binzel, R., Grundy, W., Emery, J., Rivkin, A., Thomas, C., Trilling, D., Bjorkman, K., Burgasser, A., Campins, H., Sato, T., Kasaba, Y., Ziffer, J., Mirzoyan, R., Fitzgerald, M., Bouy, H., International Outer Planet Watch Team (IOPW-PVOL), 2011, Icar, 214, 462, Long-term evolution of the aerosol debris cloud produced by the 2009 impact on Jupiter
    We present a study of the long-term evolution of the cloud of aerosols produced in the atmosphere of Jupiter by the impact of an object on 19 July 2009 (Sanchez-Lavega, A. et al. [2010]. Astrophys. J. 715, L155-L159). The work is based on images obtained during 5 months from the impact to 31 December 2009 taken in visible continuum wavelengths and from 20 July 2009 to 28 May 2010 taken in near-infrared deep hydrogen-methane absorption bands at 2.1-2.3 m. The impact cloud expanded zonally from 5000 km (July 19) to 225,000 km (29 October, about 180 in longitude), remaining meridionally localized within a latitude band from 53.5S to 61.5S planetographic latitude. During the first two months after its formation the site showed heterogeneous structure with 500-1000 km sized embedded spots. Later the reflectivity of the debris field became more homogeneous due to clump mergers. The cloud was mainly dispersed in longitude by the dominant zonal winds and their meridional shear, during the initial stages, localized motions may have been induced by thermal perturbation caused by the impact's energy deposition. The tracking of individual spots within the impact cloud shows that the westward jet at 56.5S latitude increases its eastward velocity with altitude above the tropopause by 5-10 m s -1. The corresponding vertical wind shear is low, about 1 m s -1 per scale height in agreement with previous thermal wind estimations. We found evidence for discrete localized meridional motions with speeds of 1-2 m s -1. Two numerical models are used to simulate the observed cloud dispersion. One is a pure advection of the aerosols by the winds and their shears. The other uses the EPIC code, a nonlinear calculation of the evolution of the potential vorticity field generated by a heat pulse that simulates the impact. Both models reproduce the observed global structure of the cloud and the dominant zonal dispersion of the aerosols, but not the details of the cloud morphology. The reflectivity of the impact cloud decreased exponentially with a characteristic timescale of 15 days; we can explain this behavior with a radiative transfer model of the cloud optical depth coupled to an advection model of the cloud dispersion by the wind shears. The expected sedimentation time in the stratosphere (altitude levels 5-100 mbar) for the small aerosol particles forming the cloud is 45-200 days, thus aerosols were removed vertically over the long term following their zonal dispersion. No evidence of the cloud was detected 10 months after the impact.
  43. Lellouch, E., Stansberry, J., Emery, J., Grundy, W., Cruikshank, D., 2011, Icar, 214, 701, Thermal properties of Pluto's and Charon's surfaces from Spitzer observations
    We report on thermal observations of the Pluto-Charon system acquired by the Spitzer observatory in August-September 2004. The observations, which consist of (i) photometric measurements (8 visits) with the Multiband Imaging Photometer (MIPS) at 24, 70 and 160 m and (ii) low-resolution spectra (8 visits) over 20-37 m with the Infrared Spectrometer (IRS), clearly exhibit the thermal lightcurve of Pluto/Charon at a variety of wavelengths. They further indicate a steady decrease of the system brightness temperature with increasing wavelength. Observations are analyzed by means of a thermophysical model, including the effects of thermal conduction and surface roughness, and using a multi-terrain description of Pluto and Charon surfaces in accordance with visible imaging and lightcurves, and visible and near-infrared spectroscopy. Three units are considered for Pluto, respectively covered by N 2 ice, CH 4 ice, and a tholin/H 2O mix. Essential model parameters are the thermal inertia of Pluto and Charon surfaces and the spectral and bolometric emissivity of the various units. A new and improved value of Pluto's surface thermal inertia, referring to the CH 4 and tholin/H 2O areas, is determined to be Pl = 20-30 J m -2 s -1/2 K -1 (MKS). The high-quality 24-m lightcurve permits a precise assessment of Charon's thermal emission, indicating a mean surface temperature of 55.4 2.6 K. Although Charon is on average warmer than Pluto, it is also not in instantaneous equilibrium with solar radiation. Charon's surface thermal inertia is in the range Ch = 10-150 MKS, though most model solutions point to Ch = 10-20 MKS. Pluto and Charon thermal inertias appear much lower than values expected for compact ices, probably resulting from high surface porosity and poor surface consolidation. Comparison between Charon's thermal inertia and even lower values estimated for two other H 2O-covered Kuiper-Belt objects suggests that a vertical gradient of conductivity exists in the upper surface of these bodies. Finally, the observations indicate that the spectral emissivity of methane ice is close to unity at 24 m and decreases with increasing wavelength to 0.6 at 100 m. Future observations of thermal lightcurves over 70-500 m by Herschel should be very valuable to further constrain the emissivity behavior of the Pluto terrains.
  44. Barnes, S., 2011, IAUS, 273, 465, A nonlinear model for rotating cool stars
    A simple nonlinear model is introduced here to describe the rotational evolution of main sequence cool (FGKM) stars. It is formulated only in terms of the ratio of a star's rotation period, P, to its convective turnover timescale, , and two dimensionless constants which are specified using solar- and open cluster data. The model explains the origin of the two sequences, C/fast and I/slow, of rotating stars observed in open cluster color-period diagrams, and describes their evolution from C-type to I-type through the rotational gap, g, separating them. It explains why intermediate-mass open cluster stars have the longest periods, while higher- and lower-mass cool stars have shorter periods. It provides an exact expression for the age of a rotating cool star in terms of P and , thereby generalizing gyrochronology. The possible range of initial periods is shown to contribute upto 128 Myr to the gyro age errors of solar mass field stars. A transformation to color-period space shows how this model explains some detailed features in the color-period diagrams of open clusters, including the shapes and widths of the sequences, and the observed number density of stars across these diagrams.
  45. Saar, S., Dyke, M., Meibom, S., Barnes, S., 2011, IAUS, 273, 469, The dependence of maximum starspot amplitude and the amplitude distribution on stellar properties
    We combine photometric data from field stars, plus over a dozen open clusters and associations, to explore how the maximum photometric amplitude (Amax) and the distribution of amplitudes varies with stellar properties. We find a complex variation of Amax with inverse Rossby number Ro-1, which nevertheless can be modeled well with a simple model including an increase in Amax with rotation for low Ro-1, and a maximum level. Amax may then be further affected by differential rotation and a decline at the highest Ro-1. The distribution of Aspot below Amax varies with Ro-1 : it peaks at low Aspot with a long tail towards Amax for low Ro-1, but is more uniformly distributed at higher Ro-1. We investigate further dependences of the Aspot distributions on stellar properties, and speculate on the source of these variations.
  46. Mahmud, N., Crockett, C., Johns-Krull, C., Prato, L., Hartigan, P., Jaffe, D., Beichman, C., 2011, ApJ, 736, 123, Starspot-induced Optical and Infrared Radial Velocity Variability in T Tauri Star Hubble I 4
    We report optical (~6150 A) and K-band (2.3 m) radial velocities obtained over two years for the pre-main-sequence weak-lined T Tauri star Hubble I 4. We detect periodic and near-sinusoidal radial velocity variations at both wavelengths, with a semi-amplitude of 1395 94 m s-1 in the optical and 365 80 m s-1 in the infrared. The lower velocity amplitude at the longer wavelength, combined with bisector analysis and spot modeling, indicates that there are large, cool spots on the stellar surface that are causing the radial velocity modulation. The radial velocities maintain phase coherence over hundreds of days suggesting that the starspots are long-lived. This is one of the first active stars where the spot-induced velocity modulation has been resolved in the infrared.
  47. Crossfield, I., Barman, T., Hansen, B., 2011, ApJ, 736, 132, High-resolution, Differential, Near-infrared Transmission Spectroscopy of GJ 1214b
    The nearby star GJ 1214 hosts a planet intermediate in radius and mass between Earth and Neptune, resulting in some uncertainty as to its nature. We have observed this planet, GJ 1214b, during transit with the high-resolution, near-infrared NIRSPEC spectrograph on the Keck II telescope, in order to characterize the planet's atmosphere. By cross-correlating the spectral changes through transit with a suite of theoretical atmosphere models, we search for variations associated with absorption in the planet atmosphere. Our observations are sufficient to rule out tested model atmospheres with wavelength-dependent transit depth variations >~ 5 10-4 over the wavelength range 2.1-2.4 m. Our sensitivity is limited by variable slit loss and telluric transmission effects. We find no positive signatures but successfully rule out a number of plausible atmospheric models, including the default assumption of a gaseous, H-dominated atmosphere in chemical equilibrium. Such an atmosphere can be made consistent if the absorption due to methane is reduced. Clouds can also render such an atmosphere consistent with our observations, but only if they lie higher in the atmosphere than indicated by recent optical and infrared measurements. When taken in concert with other observational constraints, our results support a model in which the atmosphere of GJ 1214b contains significant H and He, but where CH4 is depleted. If this depletion is the result of photochemical processes, it may also produce a haze that suppresses spectral features in the optical.
  48. Vercellone, S., Striani, E., Vittorini, V., Donnarumma, I., Pacciani, L., Pucella, G., Tavani, M., Raiteri, C., Villata, M., Romano, P., Fiocchi, M., Bazzano, A., Bianchin, V., Ferrigno, C., Maraschi, L., Pian, E., Turler, M., Ubertini, P., Bulgarelli, A., Chen, A., Giuliani, A., Longo, F., Barbiellini, G., Cardillo, M., Cattaneo, P., Del Monte, E., Evangelista, Y., Feroci, M., Ferrari, A., Fuschino, F., Gianotti, F., Giusti, M., Lazzarotto, F., Pellizzoni, A., Piano, G., Pilia, M., Rapisarda, M., Rappoldi, A., Sabatini, S., Soffitta, P., Trifoglio, M., Trois, A., Giommi, P., Lucarelli, F., Pittori, C., Santolamazza, P., Verrecchia, F., Agudo, I., Aller, H., Aller, M., Arkharov, A., Bach, U., Berdyugin, A., Borman, G., Chigladze, R., Efimov, Y., Efimova, N., Gomez, J., Gurwell, M., McHardy, I., Joshi, M., Kimeridze, G., Krajci, T., Kurtanidze, O., Kurtanidze, S., Larionov, V., Lindfors, E., Molina, S., Morozova, D., Nazarov, S., Nikolashvili, M., Nilsson, K., Pasanen, M., Reinthal, R., Ros, J., Sadun, A., Sakamoto, T., Sallum, S., Sergeev, S., Schwartz, R., Sigua, L., Sillanpaa, A., Sokolovsky, K., Strelnitski, V., Takalo, L., Taylor, B., Walker, G., 2011, ApJL, 736, L38, The Brightest Gamma-Ray Flaring Blazar in the Sky: AGILE and Multi-wavelength Observations of 3C 454.3 During 2010 November
    Since 2005, the blazar 3C 454.3 has shown remarkable flaring activity at all frequencies, and during the last four years it has exhibited more than one -ray flare per year, becoming the most active -ray blazar in the sky. We present for the first time the multi-wavelength AGILE, Swift, INTEGRAL, and GASP-WEBT data collected in order to explain the extraordinary -ray flare of 3C 454.3 which occurred in 2010 November. On 2010 November 20 (MJD 55520), 3C 454.3 reached a peak flux (E >100 MeV) of Fp = (6.8 1.0) 10-5 photons cm-2 s-1 on a timescale of about 12 hr, more than a factor of six higher than the flux of the brightest steady -ray source, the Vela pulsar, and more than a factor of three brighter than its previous super-flare on 2009 December 2-3. The multi-wavelength data make possible a thorough study of the present event: the comparison with the previous outbursts indicates a close similarity to the one that occurred in 2009. By comparing the broadband emission before, during, and after the -ray flare, we find that the radio, optical, and X-ray emission varies within a factor of 2-3, whereas the -ray flux by a factor of 10. This remarkable behavior is modeled by an external Compton component driven by a substantial local enhancement of soft seed photons.
  49. Barnes, J., Jones, H., Barman, T., Jones, H., Barber, R., Hansen, B., Prato, L., Rice, E., Leigh, C., Collier Cameron, A., Pinfield, D., Jenkins, J., Segransan, D., 2011, EPJWC, 16, 04001, Spectroscopic detection and characterisation of planetary atmospheres
    Space based broadband infrared observations of close orbiting extrasolar giant planets at transit and secondary eclipse have proved a successful means of determining atmospheric spectral energy distributions and molecular composition. Here, a ground-based spectroscopic technique to detect and characterise planetary atmospheres is presented. Since the planet need not be transiting, this method enables a greater sample of systems to be studied. By modelling the planetary signature as a function of phase, high resolution spectroscopy has the potential to recover the signature of molecules in planetary atmospheres.
  50. Jackson, M., Hunter, D., Lockman, F., 2011, EAS, 48, 167, Merging or Interacting? Determining the Nature of the Large-Scale Structure Around NGC 1569
    We present a preliminary large-scale, neutral Hydrogen emission map of structure around dwarf irregular (dIm) galaxy NGC 1569. These data were taken earlier this year with the Robert C. Byrd Green Bank Telescope (GBT). Our primary objective was to search for HI structure potentially connecting NGC 1569 with IC 342 as an explanation for the starburst and peculiar kinematics prevalent in NGC 1569.
  51. Borucki, W., Koch, D., Basri, G., Batalha, N., Brown, T., Bryson, S., Caldwell, D., Christensen-Dalsgaard, J., Cochran, W., DeVore, E., Dunham, E., Gautier, T., Geary, J., Gilliland, R., Gould, A., Howell, S., Jenkins, J., Latham, D., Lissauer, J., Marcy, G., Rowe, J., Sasselov, D., Boss, A., Charbonneau, D., Ciardi, D., Doyle, L., Dupree, A., Ford, E., Fortney, J., Holman, M., Seager, S., Steffen, J., Tarter, J., Welsh, W., Allen, C., Buchhave, L., Christiansen, J., Clarke, B., Das, S., Desert, J., Endl, M., Fabrycky, D., Fressin, F., Haas, M., Horch, E., Howard, A., Isaacson, H., Kjeldsen, H., Kolodziejczak, J., Kulesa, C., Li, J., Lucas, P., Machalek, P., McCarthy, D., MacQueen, P., Meibom, S., Miquel, T., Prsa, A., Quinn, S., Quintana, E., Ragozzine, D., Sherry, W., Shporer, A., Tenenbaum, P., Torres, G., Twicken, J., Van Cleve, J., Walkowicz, L., Witteborn, F., Still, M., 2011, ApJ, 736, 19, Characteristics of Planetary Candidates Observed by Kepler. II. Analysis of the First Four Months of Data
    On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (R p < 1.25 R ), 288 super-Earth-size (1.25 R <= R p < 2 R ), 662 Neptune-size (2 R <= R p < 6 R ), 165 Jupiter-size (6 R <= R p < 15 R ), and 19 up to twice the size of Jupiter (15 R <= R p < 22 R ). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. The observed number versus size distribution of planetary candidates increases to a peak at two to three times the Earth-size and then declines inversely proportional to the area of the candidate. Our current best estimates of the intrinsic frequencies of planetary candidates, after correcting for geometric and sensitivity biases, are 5% for Earth-size candidates, 8% for super-Earth-size candidates, 18% for Neptune-size candidates, 2% for Jupiter-size candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems.
  52. Porter, S., Grundy, W., 2011, ApJL, 736, L14, Post-capture Evolution of Potentially Habitable Exomoons
    The satellites of extrasolar planets (exomoons) have been recently proposed as astrobiological targets. Since giant planets in the habitable zone are thought to have migrated there, it is possible that they may have captured a former terrestrial planet or planetesimal. We therefore attempt to model the dynamical evolution of a terrestrial planet captured into orbit around a giant planet in the habitable zone of a star. We find that approximately half of loose elliptical orbits result in stable circular orbits over timescales of less than a few million years. We also find that those orbits are mostly at low inclination, but have no prograde/retrograde preference. In addition, we calculate the transit timing and duration variations for the resulting systems, and find that potentially habitable Earth-mass exomoons should be detectable.
  53. Crockett, C., Mahmud, N., Prato, L., Johns-Krull, C., Jaffe, D., Beichman, C., 2011, ApJ, 735, 78, Precision Radial Velocities with CSHELL
    Radial velocity (RV) identification of extrasolar planets has historically been dominated by optical surveys. Interest in expanding exoplanet searches to M dwarfs and young stars, however, has motivated a push to improve the precision of near-infrared RV techniques. We present our methodology for achieving 58 m s-1 precision in the K band on the M0 dwarf GJ 281 using the CSHELL spectrograph at the 3 m NASA Infrared Telescope Facility. We also demonstrate our ability to recover the known 4 M JUP exoplanet Gl 86 b and discuss the implications for success in detecting planets around 1-3 Myr old T Tauri stars.
  54. Barman, T., Macintosh, B., Konopacky, Q., Marois, C., 2011, ApJL, 735, L39, The Young Planet-mass Object 2M1207b: A Cool, Cloudy, and Methane-poor Atmosphere
    The properties of 2M1207b, a young (~8 Myr) planet-mass companion, have lacked a satisfactory explanation for some time. The combination of low luminosity, red near-IR colors, and L-type near-IR spectrum (previously consistent with T eff ~ 1600 K) implies an abnormally small radius. Early explanations for the apparent underluminosity of 2M1207b invoked an edge-on disk or the remnant of a recent protoplanetary collision. The discovery of a second planet-mass object (HR8799b) with similar luminosity and colors as 2M1207b indicates that a third explanation, one of a purely atmospheric nature, is more likely. By including clouds, non-equilibrium chemistry, and low gravity, an atmosphere with effective temperature consistent with evolution cooling-track predictions is revealed. Consequently, 2M1207b, and others like it, requires no new physics to explain nor do they belong to a new class of objects. Instead they most likely represent the natural extension of cloudy substellar atmospheres down to low T eff and log (g). If this atmosphere only explanation for 2M1207b is correct, then very young planet-mass objects with near-IR spectra similar to field T dwarfs may be rare.
  55. Agudo, I., Marscher, A., Jorstad, S., Larionov, V., Gomez, J., Lahteenmaki, A., Smith, P., Nilsson, K., Readhead, A., Aller, M., Heidt, J., Gurwell, M., Thum, C., Wehrle, A., Nikolashvili, M., Aller, H., Benitez, E., Blinov, D., Hagen-Thorn, V., Hiriart, D., Jannuzi, B., Joshi, M., Kimeridze, G., Kurtanidze, O., Kurtanidze, S., Lindfors, E., Molina, S., Morozova, D., Nieppola, E., Olmstead, A., Reinthal, R., Roca-Sogorb, M., Schmidt, G., Sigua, L., Sillanpaa, A., Takalo, L., Taylor, B., Tornikoski, M., Troitsky, I., Zook, A., Wiesemeyer, H., 2011, ApJL, 735, L10, On the Location of the -Ray Outburst Emission in the BL Lacertae Object AO 0235+164 Through Observations Across the Electromagnetic Spectrum
    We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and -ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array images at = 7 mm with ~0.15 milliarcsec resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary "core" and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight by light-travel time delays, that passes through a standing recollimation shock in the core and propagates down the jet to create the superluminal knot. The multi-wavelength light curves vary together on long timescales (months/years), but the correspondence is poorer on shorter timescales. This, as well as the variability of the polarization and the dual location of the outburst, agrees with the expectations of a multi-zone emission model in which turbulence plays a major role in modulating the synchrotron and inverse Compton fluxes.
  56. Buie, M., Trilling, D., Wasserman, L., Crudo, R., 2011, ApJS, 194, 40, A Large and Faint Photometric Catalog on the Ecliptic
    A photometric catalog, developed for the calibration of the Deep Ecliptic Survey, is presented. The catalog contains 213,272 unique sources that were measured in V and R filters and transformed to the Johnson-Cousins systems using the Landolt standard catalog. All of the sources lie within 6 of the ecliptic and cover all longitudes except for the densest stellar regions nearest the galactic center. Seventeen percent of the sources in the catalog are derived from three or more nights of observation. The catalog contains sources as faint as R ~19 but the largest fraction fall in the R ~15-16 (V ~16-17) mag range. All magnitude bins down to R = 19 have a significant fraction of objects with uncertainties <=0.1 mag.
  57. Meech, K., A'Hearn, M., Adams, J., Bacci, P., Bai, J., Barrera, L., Battelino, M., Bauer, J., Becklin, E., Bhatt, B., Biver, N., Bockelee-Morvan, D., Bodewits, D., Bohnhardt, H., Boissier, J., Bonev, B., Borghini, W., Brucato, J., Bryssinck, E., Buie, M., Canovas, H., Castellano, D., Charnley, S., Chen, W., Chiang, P., Choi, Y., Christian, D., Chuang, Y., Cochran, A., Colom, P., Combi, M., Coulson, I., Crovisier, J., Dello Russo, N., Dennerl, K., DeWahl, K., DiSanti, M., Facchini, M., Farnham, T., Fernandez, Y., Floren, H., Frisk, U., Fujiyoshi, T., Furusho, R., Fuse, T., Galli, G., Garcia-Hernandez, D., Gersch, A., Getu, Z., Gibb, E., Gillon, M., Guido, E., Guillermo, R., Hadamcik, E., Hainaut, O., Hammel, H., Harker, D., Harmon, J., Harris, W., Hartogh, P., Hashimoto, M., Hausler, B., Herter, T., Hjalmarson, A., Holland, S., Honda, M., Hosseini, S., Howell, E., Howes, N., Hsieh, H., Hsiao, H., Hutsemekers, D., Immler, S., Jackson, W., Jeffers, S., Jehin, E., Jones, T., de Juan Ovelar, M., Kaluna, H., Karlsson, T., Kawakita, H., Keane, J., Keller, L., Kelley, M., Kinoshita, D., Kiselev, N., Kleyna, J., Knight, M., Kobayashi, H., Kobulnicky, H., Kolokolova, L., Kreiny, M., Kuan, Y., Kuppers, M., Lacruz, J., Landsman, W., Lara, L., Lecacheux, A., Levasseur-Regourd, A., Li, B., Licandro, J., Ligustri, R., Lin, Z., Lippi, M., Lis, D., Lisse, C., Lovell, A., Lowry, S., Lu, H., Lundin, S., Magee-Sauer, K., Magain, P., Manfroid, J., Mazzotta Epifani, E., McKay, A., Melita, M., Mikuz, H., Milam, S., Milani, G., Min, M., Moreno, R., Mueller, B., Mumma, M., Nicolini, M., Nolan, M., Nordh, H., Nowajewski, P., Odin Team, Ootsubo, T., Paganini, L., Perrella, C., Pittichova, J., Prosperi, E., Radeva, Y., Reach, W., Remijan, A., Rengel, M., Riesen, T., Rodenhuis, M., Rodriguez, D., Russell, R., Sahu, D., Samarasinha, N., Sanchez Caso, A., Sandqvist, A., Sarid, G., Sato, M., Schleicher, D., Schwieterman, E., Sen, A., Shenoy, D., Shi, J., Shinnaka, Y., Skvarc, J., Snodgrass, C., Sitko, M., Sonnett, S., Sosseini, S., Sostero, G., Sugita, S., Swinyard, B., Szutowicz, S., Takato, N., Tanga, P., Taylor, P., Tozzi, G., Trabatti, R., Trigo-Rodriguez, J., Tubiana, C., de Val-Borro, M., Vacca, W., Vandenbussche, B., Vaubaillion, J., Velichko, F., Velichko, S., Vervack, R., Vidal-Nunez, M., Villanueva, G., Vinante, C., Vincent, J., Wang, M., Wasserman, L., Watanabe, J., Weaver, H., Weissman, P., Wolk, S., Wooden, D., Woodward, C., Yamaguchi, M., Yamashita, T., Yanamandra-Fischer, P., Yang, B., Yao, J., Yeomans, D., Zenn, T., Zhao, H., Ziffer, J., 2011, ApJL, 734, L1, EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign
    Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ~16.4 hr. Starting in 2010 August the period changed from 16.6 hr to near 19 hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO2-driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production.
  58. Grundy, W., Noll, K., Nimmo, F., Roe, H., Buie, M., Porter, S., Benecchi, S., Stephens, D., Levison, H., Stansberry, J., 2011, Icar, 213, 678, Five new and three improved mutual orbits of transneptunian binaries
    We present three improved and five new mutual orbits of transneptunian binary systems (58534) Logos-Zoe, (66652) Borasisi-Pabu, (88611) Teharonhiawako-Sawiskera, (123509) 2000 WK 183, (149780) Altjira, 2001 QY 297, 2003 QW 111, and 2003 QY 90 based on Hubble Space Telescope and Keck II laser guide star adaptive optics observations. Combining the five new orbit solutions with 17 previously known orbits yields a sample of 22 mutual orbits for which the period P, semimajor axis a, and eccentricity e have been determined. These orbits have mutual periods ranging from 5 to over 800 days, semimajor axes ranging from 1600 to 37,000 km, eccentricities ranging from 0 to 0.8, and system masses ranging from 2 10 17 to 2 10 22 kg. Based on the relative brightnesses of primaries and secondaries, most of these systems consist of near equal-sized pairs, although a few of the most massive systems are more lopsided. The observed distribution of orbital properties suggests that the most loosely-bound transneptunian binary systems are only found on dynamically cold heliocentric orbits. Of the 22 known binary mutual orbits, orientation ambiguities are now resolved for 9, of which 7 are prograde and 2 are retrograde, consistent with a random distribution of orbital orientations, but not with models predicting a strong preference for retrograde orbits. To the extent that other perturbations are not dominant, the binary systems undergo Kozai oscillations of their eccentricities and inclinations with periods of the order of tens of thousands to millions of years, some with strikingly high amplitudes.
  59. Benecchi, S., Noll, K., Stephens, D., Grundy, W., Rawlins, J., 2011, Icar, 213, 693, Optical and infrared colors of transneptunian objects observed with HST
    We present optical colors of 72 transneptunian objects (TNOs), and infrared colors of 80 TNOs obtained with the WFPC2 and NICMOS instruments, respectively, on the Hubble Space Telescope (HST). Both optical and infrared colors are available for 32 objects that overlap between the datasets. This dataset adds an especially uniform, consistent and large contribution to the overall sample of colors, particularly in the infrared. The range of our measured colors is consistent with other colors reported in the literature at both optical and infrared wavelengths. We find generally good agreement for objects measured by both us and others; 88.1% have better than 2 sigma agreement. The median absolute magnitude, H V, magnitude of our optical sample is 7.2, modestly smaller (0.5 mag) than for previous samples. The median H V in our infrared sample is 6.7. We find no new correlations between color and dynamical properties (semi-major axis, eccentricity, inclination and perihelion). We do find that colors of Classical objects with i < 6 come from a different distribution than either the Resonant or excited populations in the visible at the >99.99% level with a K-S test. The same conclusion is found in the infrared at a slightly lower significance level, 99.72%. Two Haumea collision fragments with strong near infrared ice bands are easily identified with broad HST infrared filters and point to an efficient search strategy for identifying more such objects. We find evidence for variability in (19255) 1999 VK 8, 1999 OE 4, 2000 CE 105, 1998 KG 62 and 1998 WX 31.
  60. Chatterjee, R., Marscher, A., Jorstad, S., Markowitz, A., Rivers, E., Rothschild, R., McHardy, I., Aller, M., Aller, H., Lahteenmaki, A., Tornikoski, M., Harrison, B., Agudo, I., Gomez, J., Taylor, B., Gurwell, M., 2011, ApJ, 734, 43, Connection Between the Accretion Disk and Jet in the Radio Galaxy 3C 111
    We present the results of extensive multi-frequency monitoring of the radio galaxy 3C 111 between 2004 and 2010 at X-ray (2.4-10 keV), optical (R band), and radio (14.5, 37, and 230 GHz) wave bands, as well as multi-epoch imaging with the Very Long Baseline Array (VLBA) at 43 GHz. Over the six years of observation, significant dips in the X-ray light curve are followed by ejections of bright superluminal knots in the VLBA images. This shows a clear connection between the radiative state near the black hole, where the X-rays are produced, and events in the jet. The X-ray continuum flux and Fe line intensity are strongly correlated, with a time lag shorter than 90 days and consistent with zero. This implies that the Fe line is generated within 90 lt-day of the source of the X-ray continuum. The power spectral density function of X-ray variations contains a break, with a steeper slope at shorter timescales. The break timescale of 13+12 - 6 days is commensurate with scaling according to the mass of the central black hole based on observations of Seyfert galaxies and black hole X-ray binaries (BHXRBs). The data are consistent with the standard paradigm, in which the X-rays are predominantly produced by inverse Compton scattering of thermal optical/UV seed photons from the accretion disk by a distribution of hot electronsthe coronasituated near the disk. Most of the optical emission is generated in the accretion disk due to reprocessing of the X-ray emission. The relationships that we have uncovered between the accretion disk and the jet in 3C 111, as well as in the Fanaroff-Riley class I radio galaxy 3C 120 in a previous paper, support the paradigm that active galactic nuclei and Galactic BHXRBs are fundamentally similar, with characteristic time and size scales proportional to the mass of the central black hole.
  61. Neugent, K., Massey, P., 2011, ApJ, 733, 123, The Wolf-Rayet Content of M33
    Wolf-Rayet (WR) stars are evolved massive stars, and the relative number of WC-type and WN-type WRs should vary with metallicity, providing a sensitive test of stellar evolutionary theory. The observed WC/WN ratio is much higher than that predicted by theory in some galaxies but this could be due to observational incompleteness for WN types, which have weaker lines. Previous studies of M33's WR content show a galactocentric gradient in the relative numbers of WCs and WNs, but only small regions have been surveyed with sufficient sensitivity to detect all of the WNs. Here, we present a sensitive survey for WRs covering all of M33, finding 55 new WRs, mostly of WN type. Our spectroscopy also improves the spectral types of many previously known WRs, establishing in one case that the star is actually a background quasar. The total number of spectroscopically confirmed WRs in M33 is 206, a number we argue is complete to ~5%, with most WRs residing in OB associations, although ~2% are truly isolated. The WC/WN ratio in the central regions (<2 kpc) of M33 is much higher than that predicted by the current Geneva evolutionary models, while the WC/WN ratios in the outer regions are in good accord, as are the values in the Small Magellanic Cloud and Large Magellanic Cloud. The WC/WN ratio and the WC subtype distribution both argue that the oxygen abundance gradient in M33 is significantly larger than that found by some recent studies, but are consistent with the two-component model proposed by Magrini et al.

    Observations reported here were partially obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution. MMT telescope time was granted by NOAO, through the Telescope System Instrumentation Program (TSIP). TSIP is funded by the National Science Foundation.

  62. Knight, M., Schleicher, D., 2011, AJ, 141, 183, CN Morphology Studies of Comet 103P/Hartley 2
    We report on narrowband CN imaging of Comet 103P/Hartley 2 obtained at Lowell Observatory on 39 nights from 2010 July until 2011 January. We observed two features, one generally to the north and the other generally to the south. The CN morphology varied during the apparition: no morphology was seen in July; in August and September, the northern feature dominated and appeared as a mostly face-on spiral; in October, November, and December, the northern and southern features were roughly equal in brightness and looked like more side-on corkscrews; in January, the southern feature was dominant but the morphology was indistinct due to very low signal. The morphology changed smoothly during each night and similar morphology was seen from night to night. However, the morphology did not exactly repeat each rotation cycle, suggesting that there is a small non-principal axis rotation. Based on the repetition of the morphology, we find evidence that the fundamental rotation period was increasing: 16.7 hr from August 13 to 17, 17.2 hr from September 10 to 13, 18.2 hr from October 12 to 19, and 18.7 hr from October 31 to November 7. We conducted Monte Carlo jet modeling to constrain the pole orientation and locations of the active regions based on the observed morphology. Our preliminary, self-consistent pole solution has an obliquity of 10 relative to the comet's orbital plane (i.e., it is centered near R.A. = 257 and decl. = +67 with an uncertainty around this position of about 15) and has two mid-latitude sources, one in each hemisphere.
  63. Schleicher, D., Bair, A., 2011, AJ, 141, 177, The Composition of the Interior of Comet 73P/Schwassmann-Wachmann 3: Results from Narrowband Photometry of Multiple Components
    We present analyses of and results for multiple components of Comet 73P/Schwassmann-Wachmann 3 at two apparitions. A total of eight nights of narrowband photometry were obtained during the comet's 2006 apparition from February 25 to September 24 at Lowell Observatory. The comet's very close passage of Earth and sporadic outbursts allowed us to successfully measure the primary body, "C," as well as components "B," "G," and "R." We additionally include four nights of narrowband photometry from 1995, obtained at Perth Observatory between October 19 and November 21, one to two months after the initial fragmentation event and outburst. We determined production rates for OH, NH, CN, C3, and C2, along with a proxy for the dust production, A()f, and our 2006 measurements show considerable variation in behavior among the components, and for the gas species as compared to the dust grains. The two components having the best temporal coverage, C and B, both exhibit evidence for strong seasonal effects with larger production rates prior to perihelion than after. Because C showed little or no evidence of outbursts, its derived active area (based on water production rates) appears to be dominated by ice vaporizing from the nucleus; the fractional active area of the total nucleus surface varied from 56% (2006 February) to 125% (May) and back down to 11% (September) following perihelion. Except for when Component B was in outburst, C always had higher production rates than B, implying a significantly larger effective active area on its nucleus' surface. Unlike the gas species, dust production showed large and varying trends with both aperture size and with time, implying a significant change in the properties of the dust grains during the 2006 apparition. Due to the fragmentation event in 1995, the majority of active surfaces on the various components observed in 2006 are freshly exposed from the interior of Schwassmann-Wachmann 3's nucleus, thus permitting us to directly probe the chemical composition of the relatively pristine interior. Relative abundances, expressed as production rate ratios between gas species, were compared among the four components and to values determined prior to the fragmentation, as well as to those measured in other comets. Our measurements indicate each component, to within the uncertainties, has the same composition and that this composition is consistent with that measured in the pre-fragmented nucleus. Moreover, C2 and C3 are both strongly depleted when compared to the majority of comets, placing Schwassmann-Wachmann 3 among the more extreme comets within the carbon-chain depleted class identified by A'Hearn et al. With the material released from the interior of the comet yielding comparable depletions of carbon-chain molecules as the original surface of the nucleus, we conclude that carbon-chain depletion is not caused by evolution of the surface, and so must instead reflect the primordial composition at the time and location that the comet accreted.
  64. Horch, E., van Altena, W., Howell, S., Sherry, W., Ciardi, D., 2011, AJ, 141, 180, Observations of Binary Stars with the Differential Speckle Survey Instrument. III. Measures below the Diffraction Limit of the WIYN Telescope
    In this paper, we study the ability of CCD- and electron-multiplying-CCD-based speckle imaging to obtain reliable astrometry and photometry of binary stars below the diffraction limit of the WIYN 3.5 m Telescope. We present a total of 120 measures of binary stars, 75 of which are below the diffraction limit. The measures are divided into two groups that have different measurement accuracy and precision. The first group is composed of standard speckle observations, that is, a sequence of speckle images taken in a single filter, while the second group consists of paired observations where the two observations are taken on the same observing run and in different filters. The more recent paired observations were taken simultaneously with the Differential Speckle Survey Instrument, which is a two-channel speckle imaging system. In comparing our results to the ephemeris positions of binaries with known orbits, we find that paired observations provide the opportunity to identify cases of systematic error in separation below the diffraction limit and after removing these from consideration, we obtain a linear measurement uncertainty of 3-4 mas. However, if observations are unpaired or if two observations taken in the same filter are paired, it becomes harder to identify cases of systematic error, presumably because the largest source of this error is residual atmospheric dispersion, which is color dependent. When observations are unpaired, we find that it is unwise to report separations below approximately 20 mas, as these are most susceptible to this effect. Using the final results obtained, we are able to update two older orbits in the literature and present preliminary orbits for three systems that were discovered by Hipparcos.

    The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories.

  65. Muinonen, K., Oszkiewicz, D., Pieniluoma, T., Granvik, M., Virtanen, J., 2011, sssb, 7, Asteroid orbital inversion using Markov-chain Monte Carlo methods
    No abstract found.
  66. Oszkiewicz, D., Bowell, T., Muinonen, K., Trilling, D., Penttila, A., Pieniluoma, T., Wasserman, L., 2011, sssb, 23, Asteroid physical and dynamical properties from Lowell Observatory photometric database
    No abstract found.
  67. Latham, D., Rowe, J., Quinn, S., Batalha, N., Borucki, W., Brown, T., Bryson, S., Buchhave, L., Caldwell, D., Carter, J., Christiansen, J., Ciardi, D., Cochran, W., Dunham, E., Fabrycky, D., Ford, E., Gautier, T., Gilliland, R., Holman, M., Howell, S., Ibrahim, K., Isaacson, H., Jenkins, J., Koch, D., Lissauer, J., Marcy, G., Quintana, E., Ragozzine, D., Sasselov, D., Shporer, A., Steffen, J., Welsh, W., Wohler, B., 2011, ApJL, 732, L24, A First Comparison of Kepler Planet Candidates in Single and Multiple Systems
    In this Letter, we present an overview of the rich population of systems with multiple candidate transiting planets found in the first four months of Kepler data. The census of multiples includes 115 targets that show two candidate planets, 45 with three, eight with four, and one each with five and six, for a total of 170 systems with 408 candidates. When compared to the 827 systems with only one candidate, the multiples account for 17% of the total number of systems, and one-third of all the planet candidates. We compare the characteristics of candidates found in multiples with those found in singles. False positives due to eclipsing binaries are much less common for the multiples, as expected. Singles and multiples are both dominated by planets smaller than Neptune; 69+2 - 3% for singles and 86+2 - 5% for multiples. This result, that systems with multiple transiting planets are less likely to include a transiting giant planet, suggests that close-in giant planets tend to disrupt the orbital inclinations of small planets in flat systems, or maybe even prevent the formation of such systems in the first place.
  68. Morales-Calderon, M., Stauffer, J., Hillenbrand, L., Gutermuth, R., Song, I., Rebull, L., Plavchan, P., Carpenter, J., Whitney, B., Covey, K., Alves de Oliveira, C., Winston, E., McCaughrean, M., Bouvier, J., Guieu, S., Vrba, F., Holtzman, J., Marchis, F., Hora, J., Wasserman, L., Terebey, S., Megeath, T., Guinan, E., Forbrich, J., Huelamo, N., Riviere-Marichalar, P., Barrado, D., Stapelfeldt, K., Hernandez, J., Allen, L., Ardila, D., Bayo, A., Favata, F., James, D., Werner, M., Wood, K., 2011, ApJ, 733, 50, Ysovar: The First Sensitive, Wide-area, Mid-infrared Photometric Monitoring of the Orion Nebula Cluster
    We present initial results from time-series imaging at infrared wavelengths of 0.9 deg2 in the Orion Nebula Cluster (ONC). During Fall 2009 we obtained 81 epochs of Spitzer 3.6 and 4.5 m data over 40 consecutive days. We extracted light curves with ~3% photometric accuracy for ~2000 ONC members ranging from several solar masses down to well below the hydrogen-burning mass limit. For many of the stars, we also have time-series photometry obtained at optical (Ic ) and/or near-infrared (JK s ) wavelengths. Our data set can be mined to determine stellar rotation periods, identify new pre-main-sequence eclipsing binaries, search for new substellar Orion members, and help better determine the frequency of circumstellar disks as a function of stellar mass in the ONC. Our primary focus is the unique ability of 3.6 and 4.5 m variability information to improve our understanding of inner disk processes and structure in the Class I and II young stellar objects (YSOs). In this paper, we provide a brief overview of the YSOVAR Orion data obtained in Fall 2009 and highlight our light curves for AA-Tau analogsYSOs with narrow dips in flux, most probably due to disk density structures passing through our line of sight. Detailed follow-up observations are needed in order to better quantify the nature of the obscuring bodies and what this implies for the structure of the inner disks of YSOs.
  69. Barman, T., Macintosh, B., Konopacky, Q., Marois, C., 2011, ApJ, 733, 65, Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b
    Using the integral field spectrograph OSIRIS, on the Keck II telescope, broad near-infrared H- and K-band spectra of the young exoplanet HR8799b have been obtained. In addition, six new narrowband photometric measurements have been taken across the H and K bands. These data are combined with previously published photometry for an analysis of the planet's atmospheric properties. Thick photospheric dust cloud opacity is invoked to explain the planet's red near-IR colors and relatively smooth near-IR spectrum. Strong water absorption is detected, indicating a hydrogen-rich atmosphere. Only weak CH4 absorption is detected at K band, indicating efficient vertical mixing and a disequilibrium CO/CH4 ratio at photospheric depths. The H-band spectrum has a distinct triangular shape consistent with low surface gravity. New giant planet atmosphere models are compared to these data with best-fitting bulk parameters, T eff = 1100 K 100 and log (g) = 3.5 0.5 (for solar composition). Given the observed luminosity (log L obs/L sun ~ - 5.1), these values correspond to a radius of 0.75 R Jup +0.17 - 0.12 and a mass of ~0.72 M Jup +2.6 - 0.6strikingly inconsistent with interior/evolution models. Enhanced metallicity (up to ~10 that of the Sun) along with thick clouds and non-equilibrium chemistry are likely required to reproduce the complete ensemble of spectroscopic and photometric data and the low effective temperatures (<1000 K) required by the evolution models.
  70. Meibom, S., Barnes, S., Latham, D., Batalha, N., Borucki, W., Koch, D., Basri, G., Walkowicz, L., Janes, K., Jenkins, J., Van Cleve, J., Haas, M., Bryson, S., Dupree, A., Furesz, G., Szentgyorgyi, A., Buchhave, L., Clarke, B., Twicken, J., Quintana, E., 2011, ApJL, 733, L9, The Kepler Cluster Study: Stellar Rotation in NGC 6811
    We present rotation periods for 71 single dwarf members of the open cluster NGC 6811 determined using photometry from NASA's Kepler mission. The results are the first from The Kepler Cluster Study, which combines Kepler's photometry with ground-based spectroscopy for cluster membership and binarity. The rotation periods delineate a tight sequence in the NGC 6811 color-period diagram from ~1 day at mid-F to ~11 days at early-K spectral type. This result extends to 1 Gyr similar prior results in the ~600 Myr Hyades and Praesepe clusters, suggesting that rotation periods for cool dwarf stars delineate a well-defined surface in the three-dimensional space of color (mass), rotation, and age. It implies that reliable ages can be derived for field dwarf stars with measured colors and rotation periods, and it promises to enable further understanding of various aspects of stellar rotation and activity for cool stars.
  71. Platais, I., Girard, T., Vieira, K., Lopez, C., Loomis, C., McLean, B., Pourbaix, D., Moraux, E., Mermilliod, J., James, D., Cargile, P., Barnes, S., Castillo, D., 2011, MNRAS, 413, 1024, A deep proper-motion survey of the nearby open cluster Blanco 1
    We provide two comprehensive catalogues of positions and proper motions in the area of open cluster Blanco 1. The main catalogue, CTLGM, contains 6271 objects down to V 18.5 and covers a circular 11 deg2 area. The accuracy of CTLGM proper motions, at about 0.3-0.5 mas yr-1 for well-measured stars, permits an excellent segregation between the cluster and field stars. The vector-point diagram of proper motions indicates an estimated total of 165 cluster members among the stars in our sample, while 314 stars with < 2.5 mas yr-1 have membership probabilities P 1 per cent. We also explored the astrometric potential of the Catalogue of Objects and Measured Parameters from All Sky Surveys (COMPASS) data base in order to obtain additional proper motions for fainter stars in the area of Blanco 1. This effort produced the second catalogue of proper motions, CTLGD, containing 11 598 objects down to V 21. A total of 4273 objects are common between the two catalogues. The accuracy of proper motions in CTLGD ranges from 1.0 to 6 mas yr-1. A combination of both proper-motion catalogues was instrumental in confirming that Blanco 1 contains a large population of M dwarfs (150 down to M5 V - the limit of our survey). In many respects, Blanco 1 is a scaled down twin of the Pleiades. The noted discrepancy between the distance from a new Hipparcos parallax of Blanco 1 and the cluster's photometric distance, at least partially, might be due to the apparent correlation between parallax and proper motion in right ascension for the ensemble of cluster members.
  72. Meech, K., Pittichova, J., Yang, B., Zenn, A., Belton, M., A'Hearn, M., Bagnulo, S., Bai, J., Barrera, L., Bauer, J., Bedient, J., Bhatt, B., Boehnhardt, H., Brosch, N., Buie, M., Candia, P., Chen, W., Chesley, S., Chiang, P., Choi, Y., Cochran, A., Duddy, S., Farnham, T., Fernandez, Y., Gutierrez, P., Hainaut, O., Hampton, D., Herrmann, K., Hsieh, H., Kadooka, M., Kaluna, H., Keane, J., Kim, M., Kleyna, J., Krisciunas, K., Lauer, T., Lara, L., Licandro, J., Lowry, S., McFadden, L., Moskovitz, N., Mueller, B., Polishook, D., Raja, N., Riesen, T., Sahu, D., Samarasinha, N., Sarid, G., Sekiguchi, T., Sonnett, S., Suntzeff, N., Taylor, B., Tozzi, G., Vasundhara, R., Vincent, J., Wasserman, L., Webster-Schultz, B., Zhao, H., 2011, Icar, 213, 323, Deep Impact, Stardust-NExT and the behavior of Comet 9P/Tempel 1 from 1997 to 2010
    We present observational data for Comet 9P/Tempel 1 taken from 1997 through 2010 in an international collaboration in support of the Deep Impact and Stardust-NExT missions. The data were obtained to characterize the nucleus prior to the Deep Impact 2005 encounter, and to enable us to understand the rotation state in order to make a time of arrival adjustment in February 2010 that would allow us to image at least 25% of the nucleus seen by the Deep Impact spacecraft to better than 80 m/pixel, and to image the crater made during the encounter, if possible. In total, 500 whole or partial nights were allocated to this project at 14 observatories worldwide, utilizing 25 telescopes. Seventy percent of these nights yielded useful data. The data were used to determine the linear phase coefficient for the comet in the R-band to be 0.045 0.001 mag deg -1 from 1 to 16. Cometary activity was observed to begin inbound near r 4.0 AU and the activity ended near r 4.6 AU as seen from the heliocentric secular light curves, water-sublimation models and from dust dynamical modeling. The light curve exhibits a significant pre- and post-perihelion brightness and activity asymmetry. There was a secular decrease in activity between the 2000 and 2005 perihelion passages of 20%. The post-perihelion light curve cannot be easily explained by a simple decrease in solar insolation or observing geometry. CN emission was detected in the comet at 2.43 AU pre-perihelion, and by r = 2.24 AU emission from C 2 and C 3 were evident. In December 2004 the production rate of CN increased from 1.8 10 23 mol s -1 to QCN = 2.75 10 23 mol s -1 in early January 2005 and 9.3 10 24 mol s -1 on June 6, 2005 at r = 1.53 AU.
  73. Belton, M., Meech, K., Chesley, S., Pittichova, J., Carcich, B., Drahus, M., Harris, A., Gillam, S., Veverka, J., Mastrodemos, N., Owen, W., A'Hearn, M., Bagnulo, S., Bai, J., Barrera, L., Bastien, F., Bauer, J., Bedient, J., Bhatt, B., Boehnhardt, H., Brosch, N., Buie, M., Candia, P., Chen, W., Chiang, P., Choi, Y., Cochran, A., Crockett, C., Duddy, S., Farnham, T., Fernandez, Y., Gutierrez, P., Hainaut, O., Hampton, D., Herrmann, K., Hsieh, H., Kadooka, M., Kaluna, H., Keane, J., Kim, M., Klaasen, K., Kleyna, J., Krisciunas, K., Lara, L., Lauer, T., Li, J., Licandro, J., Lisse, C., Lowry, S., McFadden, L., Moskovitz, N., Mueller, B., Polishook, D., Raja, N., Riesen, T., Sahu, D., Samarasinha, N., Sarid, G., Sekiguchi, T., Sonnett, S., Suntzeff, N., Taylor, B., Thomas, P., Tozzi, G., Vasundhara, R., Vincent, J., Wasserman, L., Webster-Schultz, B., Yang, B., Zenn, T., Zhao, H., 2011, Icar, 213, 345, Stardust-NExT, Deep Impact, and the accelerating spin of 9P/Tempel 1
    The evolution of the spin rate of Comet 9P/Tempel 1 through two perihelion passages (in 2000 and 2005) is determined from 1922 Earth-based observations taken over a period of 13 year as part of a World-Wide observing campaign and from 2888 observations taken over a period of 50 days from the Deep Impact spacecraft. We determine the following sidereal spin rates (periods): 209.023 0.025/dy (41.335 0.005 h) prior to the 2000 perihelion passage, 210.448 0.016/dy (41.055 0.003 h) for the interval between the 2000 and 2005 perihelion passages, 211.856 0.030/dy (40.783 0.006 h) from Deep Impact photometry just prior to the 2005 perihelion passage, and 211.625 0.012/dy (40.827 0.002 h) in the interval 2006-2010 following the 2005 perihelion passage. The period decreased by 16.8 0.3 min during the 2000 passage and by 13.7 0.2 min during the 2005 passage suggesting a secular decrease in the net torque. The change in spin rate is asymmetric with respect to perihelion with the maximum net torque being applied on approach to perihelion. The Deep Impact data alone show that the spin rate was increasing at a rate of 0.024 0.003/dy/dy at JD2453530.60510 (i.e., 25.134 dy before impact), which provides independent confirmation of the change seen in the Earth-based observations. The rotational phase of the nucleus at times before and after each perihelion and at the Deep Impact encounter is estimated based on the Thomas et al. (Thomas et al. [2007]. Icarus 187, 4-15) pole and longitude system. The possibility of a 180 error in the rotational phase is assessed and found to be significant. Analytical and physical modeling of the behavior of the spin rate through of each perihelion is presented and used as a basis to predict the rotational state of the nucleus at the time of the nominal (i.e., prior to February 2010) Stardust-NExT encounter on 2011 February 14 at 20:42. We find that a net torque in the range of 0.3-2.5 10 7 kg m 2 s -2 acts on the nucleus during perihelion passage. The spin rate initially slows down on approach to perihelion and then passes through a minimum. It then accelerates rapidly as it passes through perihelion eventually reaching a maximum post-perihelion. It then decreases to a stable value as the nucleus moves away from the Sun. We find that the pole direction is unlikely to precess by more than 1 per perihelion passage. The trend of the period with time and the fact that the modeled peak torque occurs before perihelion are in agreement with published accounts of trends in water production rate and suggests that widespread H 2O out-gassing from the surface is largely responsible for the observed spin-up.
  74. Witte, S., Helling, C., Barman, T., Heidrich, N., Hauschildt, P., 2011, A&A, 529, A44, Dust in brown dwarfs and extra-solar planets. III. Testing synthetic spectra on observations
    Context. This work is concerned with dust formation in ultra-cool atmospheres, encompassing the latest type stars, brown dwarfs, and hot giant exoplanets. Dust represents one of the most important and yet least understood sources of opacity in these types of objects.
    Aims: We compare our model spectra with SpeX data in order to draw conclusions about the dust cloud structure and related quantities in ultra-cool atmospheres.
    Methods: We use the self-consistent Drift-Phoenix atmosphere code, which features a kinetic dust formation mechanism and accounts for the dust cloud influence on the spectra.
    Results: We present fits of our latest model spectra to observations that cover a wide range of our model grid. The results are remarkably good, yielding significant improvement over the older Cond-/Dusty-Phoenix models, especially in the L-dwarf regime. The new models are able to properly reproduce observed spectra, including complicated features such as the molecular band strengths. This raises confidence in the reliability of our dust-modeling approach.
    Conclusions: We demonstrate that our code produces excellent results concerning the fitting with observations. This suggests that our dust cloud and atmosphere structures are reasonably accurate. Like all other current cloud models, ours is not able to produce satisfying results for spectral types later than L6 without manually tuning down the amount of dust. Our results show the formation of convective cells within the cloud, which are able to destroy the lower cloud parts. The dust opacity is reduced significantly without the need to tune the dust cloud thickness. There are indications that the cycle of dust accumulation and cloud destruction by convection is time-dependent on rather long timescales. Considering a statistical distribution of locally variable dust clouds over a dwarf's surface can result in a large number of spectral configurations for the same model atmosphere parameters, hence introducing an additional and more or less random degree of freedom to those atmospheres. Without resorting to the model atmosphere parameters, this alone can account for the unusually red and blue objects that have been discovered.
  75. Grundy, W., Morrison, S., Bovyn, M., Tegler, S., Cornelison, D., 2011, Icar, 212, 941, Remote sensing D/H ratios in methane ice: Temperature-dependent absorption coefficients of CH 3D in methane ice and in nitrogen ice
    The existence of strong absorption bands of singly deuterated methane (CH 3D) at wavelengths where normal methane (CH 4) absorbs comparatively weakly could enable remote measurement of D/H ratios in methane ice on outer Solar System bodies. We performed laboratory transmission spectroscopy experiments, recording spectra at wavelengths from 1 to 6 m to study CH 3D bands at 2.47, 2.87, and 4.56 m, wavelengths where ordinary methane absorption is weak. We report temperature-dependent absorption coefficients of these bands when the CH 3D is diluted in CH 4 ice and also when it is dissolved in N 2 ice, and describe how these absorption coefficients can be combined with data from the literature to simulate arbitrary D/H ratio absorption coefficients for CH 4 ice and for CH 4 in N 2 ice. We anticipate these results motivating new telescopic observations to measure D/H ratios in CH 4 ice on Triton, Pluto, Eris, and Makemake.
  76. Batalha, N., Borucki, W., Bryson, S., Buchhave, L., Caldwell, D., Christensen-Dalsgaard, J., Ciardi, D., Dunham, E., Fressin, F., Gautier, T., Gilliland, R., Haas, M., Howell, S., Jenkins, J., Kjeldsen, H., Koch, D., Latham, D., Lissauer, J., Marcy, G., Rowe, J., Sasselov, D., Seager, S., Steffen, J., Torres, G., Basri, G., Brown, T., Charbonneau, D., Christiansen, J., Clarke, B., Cochran, W., Dupree, A., Fabrycky, D., Fischer, D., Ford, E., Fortney, J., Girouard, F., Holman, M., Johnson, J., Isaacson, H., Klaus, T., Machalek, P., Moorehead, A., Morehead, R., Ragozzine, D., Tenenbaum, P., Twicken, J., Quinn, S., VanCleve, J., Walkowicz, L., Welsh, W., Devore, E., Gould, A., 2011, ApJ, 729, 27, Kepler's First Rocky Planet: Kepler-10b
    NASA's Kepler Mission uses transit photometry to determine the frequency of Earth-size planets in or near the habitable zone of Sun-like stars. The mission reached a milestone toward meeting that goal: the discovery of its first rocky planet, Kepler-10b. Two distinct sets of transit events were detected: (1) a 152 4 ppm dimming lasting 1.811 0.024 hr with ephemeris T [BJD] =2454964.57375+0.00060 -0.00082 + N*0.837495+0.000004 -0.000005 days and (2) a 376 9 ppm dimming lasting 6.86 0.07 hr with ephemeris T [BJD] =2454971.6761+0.0020 -0.0023 + N*45.29485+0.00065 -0.00076 days. Statistical tests on the photometric and pixel flux time series established the viability of the planet candidates triggering ground-based follow-up observations. Forty precision Doppler measurements were used to confirm that the short-period transit event is due to a planetary companion. The parent star is bright enough for asteroseismic analysis. Photometry was collected at 1 minute cadence for >4 months from which we detected 19 distinct pulsation frequencies. Modeling the frequencies resulted in precise knowledge of the fundamental stellar properties. Kepler-10 is a relatively old (11.9 4.5 Gyr) but otherwise Sun-like main-sequence star with T eff = 5627 44 K, M sstarf = 0.895 0.060 M sun, and R sstarf = 1.056 0.021 R sun. Physical models simultaneously fit to the transit light curves and the precision Doppler measurements yielded tight constraints on the properties of Kepler-10b that speak to its rocky composition: M P = 4.56+1.17 -1.29 M , R P = 1.416+0.033 -0.036 R , and P = 8.8+2.1 -2.9 g cm-3. Kepler-10b is the smallest transiting exoplanet discovered to date.

    Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology.

  77. Barnes, S., Kim, Y., 2011, ApJ, 729, 150, Erratum: "Angular Momentum Loss from Cool Stars: An Empirical Expression and Connection to Stellar Activity" (2010, ApJ, 721, 675)
    No abstract found.
  78. Bullock, E., Szkody, P., Mukadam, A., Borges, B., Fraga, L., Gansicke, B., Harrison, T., Henden, A., Holtzman, J., Howell, S., Lawson, W., Levine, S., Plotkin, R., Seibert, M., Templeton, M., Teske, J., Vrba, F., 2011, AJ, 141, 84, GALEX and Optical Observations of GW Librae during the Long Decline from Superoutburst
    The prototype of accreting, pulsating white dwarfs (GW Lib) underwent a large amplitude dwarf nova outburst in 2007. We used ultraviolet data from Galaxy Evolution Explorer and ground-based optical photometry and spectroscopy to follow GW Lib for three years following this outburst. Several variations are apparent during this interval. The optical shows a superhump modulation in the months following outburst, while a 19 minute quasi-periodic modulation lasting for several months is apparent in the year after outburst. A long timescale (about 4 hr) modulation first appears in the UV a year after outburst and increases in amplitude in the following years. This variation also appears in the optical two years after outburst but is not in phase with the UV. The pre-outburst pulsations are not yet visible after three years, likely indicating the white dwarf has not returned to its quiescent state.

    Based on observations made with the NASA Galaxy Evolution Explorer and with the Apache Point Observatory (APO) 3.5 m telescope. GALEX is operated for NASA by the California Institute of Technology under NASA contract NAS5-98034. APO is owned and operated by the Astrophysical Research Consortium (ARC).

  79. Archinal, B., A'Hearn, M., Bowell, E., Conrad, A., Consolmagno, G., Courtin, R., Fukushima, T., Hestroffer, D., Hilton, J., Krasinsky, G., Neumann, G., Oberst, J., Seidelmann, P., Stooke, P., Tholen, D., Thomas, P., Williams, I., 2011, CeMDA, 109, 101, Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009
    Every three years the IAU Working Group on Cartographic Coordinates and Rotational Elements revises tables giving the directions of the poles of rotation and the prime meridians of the planets, satellites, minor planets, and comets. This report takes into account the IAU Working Group for Planetary System Nomenclature (WGPSN) and the IAU Committee on Small Body Nomenclature (CSBN) definition of dwarf planets, introduces improved values for the pole and rotation rate of Mercury, returns the rotation rate of Jupiter to a previous value, introduces improved values for the rotation of five satellites of Saturn, and adds the equatorial radius of the Sun for comparison. It also adds or updates size and shape information for the Earth, Mars' satellites Deimos and Phobos, the four Galilean satellites of Jupiter, and 22 satellites of Saturn. Pole, rotation, and size information has been added for the asteroids (21) Lutetia, (511) Davida, and (2867) Steins. Pole and rotation information has been added for (2) Pallas and (21) Lutetia. Pole and rotation and mean radius information has been added for (1) Ceres. Pole information has been updated for (4) Vesta. The high precision realization for the pole and rotation rate of the Moon is updated. Alternative orientation models for Mars, Jupiter, and Saturn are noted. The Working Group also reaffirms that once an observable feature at a defined longitude is chosen, a longitude definition origin should not change except under unusual circumstances. It is also noted that alternative coordinate systems may exist for various (e.g. dynamical) purposes, but specific cartographic coordinate system information continues to be recommended for each body. The Working Group elaborates on its purpose, and also announces its plans to occasionally provide limited updates to its recommendations via its website, in order to address community needs for some updates more often than every 3 years. Brief recommendations are also made to the general planetary community regarding the need for controlled products, and improved or consensus rotation models for Mars, Jupiter, and Saturn.
  80. Borucki, W., Koch, D., Basri, G., Batalha, N., Boss, A., Brown, T., Caldwell, D., Christensen-Dalsgaard, J., Cochran, W., DeVore, E., Dunham, E., Dupree, A., Gautier, T., Geary, J., Gilliland, R., Gould, A., Howell, S., Jenkins, J., Kjeldsen, H., Latham, D., Lissauer, J., Marcy, G., Monet, D., Sasselov, D., Tarter, J., Charbonneau, D., Doyle, L., Ford, E., Fortney, J., Holman, M., Seager, S., Steffen, J., Welsh, W., Allen, C., Bryson, S., Buchhave, L., Chandrasekaran, H., Christiansen, J., Ciardi, D., Clarke, B., Dotson, J., Endl, M., Fischer, D., Fressin, F., Haas, M., Horch, E., Howard, A., Isaacson, H., Kolodziejczak, J., Li, J., MacQueen, P., Meibom, S., Prsa, A., Quintana, E., Rowe, J., Sherry, W., Tenenbaum, P., Torres, G., Twicken, J., Van Cleve, J., Walkowicz, L., Wu, H., 2011, ApJ, 728, 117, Characteristics of Kepler Planetary Candidates Based on the First Data Set
    In the spring of 2009, the Kepler Mission commenced high-precision photometry on nearly 156,000 stars to determine the frequency and characteristics of small exoplanets, conduct a guest observer program, and obtain asteroseismic data on a wide variety of stars. On 2010 June 15, the Kepler Mission released most of the data from the first quarter of observations. At the time of this data release, 705 stars from this first data set have exoplanet candidates with sizes from as small as that of Earth to larger than that of Jupiter. Here we give the identity and characteristics of 305 released stars with planetary candidates. Data for the remaining 400 stars with planetary candidates will be released in 2011 February. More than half the candidates on the released list have radii less than half that of Jupiter. Five candidates are present in and near the habitable zone; two near super-Earth size, and three bracketing the size of Jupiter. The released stars also include five possible multi-planet systems. One of these has two Neptune-size (2.3 and 2.5 Earth radius) candidates with near-resonant periods.
  81. Adams, E., Lopez-Morales, M., Elliot, J., Seager, S., Osip, D., 2011, ApJ, 728, 125, Transit Timing Variation Analysis of OGLE-TR-132b with Seven New Transits
    We report the results of the first transit timing variation analysis of the very hot Jupiter OGLE-TR-132b, using 10 transits collected over a seven-year period. Our analysis combines three previously published transit light curves with seven new transits, which were observed between 2008 February and 2009 May with the new MagIC-e2V instrument on the Magellan Telescopes in Chile. We provide a revised planetary radius of Rp = 1.23 0.07RJ , which is slightly larger, but consistent within the errors, than that given by previously published results. Analysis of the planet-to-star radius ratio, orbital separation, inclination, and transit duration reveals no apparent variation in any of those parameters during the time span observed. We also find no sign of transit timing variations larger than -108 49 s, with most residuals very close to zero. This allows us to place an upper limit of 5-10 M for a coplanar, low-eccentricity perturber in either the 2:1 or 3:2 mean-motion resonance with OGLE-TR-132b. We similarly find that the data are entirely consistent with a constant orbital period and there is no evidence for orbital decay within the limits of precision of our data.

    This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  82. Lissauer, J., Fabrycky, D., Ford, E., Borucki, W., Fressin, F., Marcy, G., Orosz, J., Rowe, J., Torres, G., Welsh, W., Batalha, N., Bryson, S., Buchhave, L., Caldwell, D., Carter, J., Charbonneau, D., Christiansen, J., Cochran, W., Desert, J., Dunham, E., Fanelli, M., Fortney, J., Gautier, T., Geary, J., Gilliland, R., Haas, M., Hall, J., Holman, M., Koch, D., Latham, D., Lopez, E., McCauliff, S., Miller, N., Morehead, R., Quintana, E., Ragozzine, D., Sasselov, D., Short, D., Steffen, J., 2011, Natur, 470, 53, A closely packed system of low-mass, low-density planets transiting Kepler-11
    When an extrasolar planet passes in front of (transits) its star, its radius can be measured from the decrease in starlight and its orbital period from the time between transits. Multiple planets transiting the same star reveal much more: period ratios determine stability and dynamics, mutual gravitational interactions reflect planet masses and orbital shapes, and the fraction of transiting planets observed as multiples has implications for the planarity of planetary systems. But few stars have more than one known transiting planet, and none has more than three. Here we report Kepler spacecraft observations of a single Sun-like star, which we call Kepler-11, that reveal six transiting planets, five with orbital periods between 10 and 47days and a sixth planet with a longer period. The five inner planets are among the smallest for which mass and size have both been measured, and these measurements imply substantial envelopes of light gases. The degree of coplanarity and proximity of the planetary orbits imply energy dissipation near the end of planet formation.
  83. Horch, E., Gomez, S., Sherry, W., Howell, S., Ciardi, D., Anderson, L., van Altena, W., 2011, AJ, 141, 45, Observations of Binary Stars with the Differential Speckle Survey Instrument. II. Hipparcos Stars Observed in 2010 January and June
    The results of 497 speckle observations of Hipparcos stars and selected other targets are presented. Of these, 367 were resolved into components and 130 were unresolved. The data were obtained using the Differential Speckle Survey Instrument at the WIYN 3.5 m Telescope. (The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories.) Since the first paper in this series, the instrument has been upgraded so that it now uses two electron-multiplying CCD cameras. The measurement precision obtained when comparing to ephemeris positions of binaries with very well known orbits is approximately 1-2 mas in separation and better than 0fdg6 in position angle. Differential photometry is found to be in very good agreement with Hipparcos measures in cases where the comparison is most relevant. We derive preliminary orbits for two systems.
  84. Torres, G., Fressin, F., Batalha, N., Borucki, W., Brown, T., Bryson, S., Buchhave, L., Charbonneau, D., Ciardi, D., Dunham, E., Fabrycky, D., Ford, E., Gautier, T., Gilliland, R., Holman, M., Howell, S., Isaacson, H., Jenkins, J., Koch, D., Latham, D., Lissauer, J., Marcy, G., Monet, D., Prsa, A., Quinn, S., Ragozzine, D., Rowe, J., Sasselov, D., Steffen, J., Welsh, W., 2011, ApJ, 727, 24, Modeling Kepler Transit Light Curves as False Positives: Rejection of Blend Scenarios for Kepler-9, and Validation of Kepler-9 d, A Super-earth-size Planet in a Multiple System
    Light curves from the Kepler Mission contain valuable information on the nature of the phenomena producing the transit-like signals. To assist in exploring the possibility that they are due to an astrophysical false positive, we describe a procedure (BLENDER) to model the photometry in terms of a "blend" rather than a planet orbiting a star. A blend may consist of a background or foreground eclipsing binary (or star-planet pair) whose eclipses are attenuated by the light of the candidate and possibly other stars within the photometric aperture. We apply BLENDER to the case of Kepler-9 (KIC 3323887), a target harboring two previously confirmed Saturn-size planets (Kepler-9 b and Kepler-9 c) showing transit timing variations, and an additional shallower signal with a 1.59 day period suggesting the presence of a super-Earth-size planet. Using BLENDER together with constraints from other follow-up observations we are able to rule out all blends for the two deeper signals and provide independent validation of their planetary nature. For the shallower signal, we rule out a large fraction of the false positives that might mimic the transits. The false alarm rate for remaining blends depends in part (and inversely) on the unknown frequency of small-size planets. Based on several realistic estimates of this frequency, we conclude with very high confidence that this small signal is due to a super-Earth-size planet (Kepler-9 d) in a multiple system, rather than a false positive. The radius is determined to be 1.64+0.19 -0.14 R , and current spectroscopic observations are as yet insufficient to establish its mass.
  85. Meynet, G., Georgy, C., Hirschi, R., Maeder, A., Massey, P., Przybilla, N., Nieva, M., 2011, BSRSL, 80, 266, Red Supergiants, Luminous Blue Variables and Wolf-Rayet stars: the single massive star perspective
    We discuss, in the context of the single star scenario, the nature of the progenitors of Red Supergiants (RSG), of Luminous Blue Variables (LBV) and of Wolf-Rayet (WR) stars. These three different populations correspond to evolved phases of Main-Sequence (MS) OB stars. Axial rotation and mass loss have a great influence on massive star evolution in general and more specifically on the durations of these different phases. Moderate rotation and mass loss, during the MS phase, favor the evolution towards the RSG stage. Fast rotation and strong mass loss during the MS phase, in contrast, prevent the star from becoming a RSG and allow the star to pass directly from the OB star phase into the WR phase. Mass loss during the RSG stage may make the star evolve back in the blue part of the HR diagram. We argue that such an evolution may be more common than presently accounted for in stellar models. This might be the reason for the lack of type IIP SNe with RSG progenitors having initial masses between 18 and 30 M_. The LBVs do appear as a possible transition phase between O and WR stars or between WNL and WNE stars. Fast rotation and/or strong mass loss during the Main-Sequence phase prevent the formation of LBV stars. The mechanisms driving the very strong ejections shown by LBV stars are still unknown. We present some arguments showing that axial rotation together with the proximity of the Eddington limit may play a role in driving the shell ejections. Rotation and mass loss favor the formation of Wolf-Rayet stars. The fact that WR stars and RSGs rarely occur in the same coeval populations indicates that the mass range of these two populations is different, WR stars originating from more massive stars than RSGs. Single star evolution models predict variations with the metallicity of the number ratios of Type Ibc to Type II supernovae, of Type Ib to Type II and of Type Ic to Type II, which are compatible with observations, provided that many stars leaving a black hole as a remnant produce an observable supernova event.
  86. Rosero, V., Prato, L., Wasserman, L., Rodgers, B., 2011, AJ, 141, 13, Orbital Solutions for Two Young, Low-mass Spectroscopic Binaries in Ophiuchus
    We report the orbital parameters for ROXR1 14 and RX J1622.7-2325Nw, two young, low-mass, and double-lined spectroscopic binaries recently discovered in the Ophiuchus star-forming region. Accurate orbital solutions were determined from over a dozen high-resolution spectra taken with the Keck II and Gemini South telescopes. These objects are T Tauri stars with mass ratios close to unity and periods of ~5 and ~3 days, respectively. In particular, RX J1622.7-2325Nw shows a non-circularized orbit with an eccentricity of 0.30, higher than any other short-period pre-main-sequence (PMS) spectroscopic binary known to date. We speculate that the orbit of RX J1622.7-2325Nw has not yet circularized because of the perturbing action of a ~1'' companion, itself a close visual pair. A comparison of known young spectroscopic binaries (SBs) and main-sequence (MS) SBs in the eccentricity-period plane shows an indistinguishable distribution of the two populations, implying that orbital circularization occurs in the first 1 Myr of a star's lifetime. With the results presented in this paper we increase by ~4% the small sample of PMS spectroscopic binary stars with known orbital elements.
  87. Massey, P., Olsen, K., Hodge, P., Jacoby, G., McNeill, R., Smith, R., Strong, S., 2011, AJ, 141, 28, Erratum: "A Survey of Local Group Galaxies Currently Forming Stars. II. UBVRI Photometry of Stars in Seven Dwarfs and a Comparison of the Entire Sample" (2007, AJ, 133, 2393)
    No abstract found.
  88. Agudo, I., Jorstad, S., Marscher, A., Larionov, V., Gomez, J., Lahteenmaki, A., Gurwell, M., Smith, P., Wiesemeyer, H., Thum, C., Heidt, J., Blinov, D., D'Arcangelo, F., Hagen-Thorn, V., Morozova, D., Nieppola, E., Roca-Sogorb, M., Schmidt, G., Taylor, B., Tornikoski, M., Troitsky, I., 2011, ApJL, 726, L13, Location of -ray Flare Emission in the Jet of the BL Lacertae Object OJ287 More than 14 pc from the Central Engine
    We combine time-dependent multi-waveband flux and linear polarization observations with submilliarcsecond-scale polarimetric images at = 7 mm of the BL Lacertae type blazar OJ287 to locate the -ray emission in prominent flares in the jet of the source >14 pc from the central engine. We demonstrate a highly significant correlation between the strongest -ray and millimeter-wave flares through Monte Carlo simulations. The two reported -ray peaks occurred near the beginning of two major millimeter-wave outbursts, each of which is associated with a linear polarization maximum at millimeter wavelengths. Our very long baseline array observations indicate that the two millimeter-wave flares originated in the second of two features in the jet that are separated by >14 pc. The simultaneity of the peak of the higher-amplitude -ray flare and the maximum in polarization of the second jet feature implies that the -ray and millimeter-wave flares are cospatial and occur >14 pc from the central engine. We also associate two optical flares, accompanied by sharp polarization peaks, with the two -ray events. The multi-waveband behavior is most easily explained if the -rays arise from synchrotron self-Compton scattering of optical photons from the flares. We propose that flares are triggered by interaction of moving plasma blobs with a standing shock. The -ray and optical emission is quenched by inverse Compton losses as synchrotron photons from the newly shocked plasma cross the emission region. The millimeter-wave polarization is high at the onset of a flare, but decreases as the electrons emitting at these wavelengths penetrate less polarized regions.
  89. Knight, M., Farnham, T., Schleicher, D., Schwieterman, E., 2011, AJ, 141, 2, The Increasing Rotation Period of Comet 10P/Tempel 2
    We imaged comet 10P/Tempel 2 on 32 nights from 1999 April through 2000 March. R-band light curves were obtained on 11 of these nights from 1999 April through 1999 June, prior to both the onset of significant coma activity and perihelion. Phasing of the data yields a double-peaked light curve and indicates a nucleus rotational period of 8.941 0.002 hr with a peak-to-peak amplitude of ~0.75 mag. Our data are sufficient to rule out all other possible double-peaked solutions as well as the single- and triple-peaked solutions. This rotation period agrees with one of five possible solutions found in post-perihelion data from 1994 by Mueller and Ferrin (Icarus, 123, 463-477) and unambiguously eliminates their remaining four solutions. We applied our same techniques to published light curves from 1988 which were obtained at an equivalent orbital position and viewing geometry as in 1999. We found a rotation period of 8.932 0.001 hr in 1988, consistent with the findings of previous authors and incompatible with our 1999 solution. This reveals that Tempel 2 spun-down by ~32 s between 1988 and 1999 (two intervening perihelion passages). If the spin-down is due to a systematic torque, then the rotation period prior to perihelion during the 2010 apparition is expected to be an additional 32 s longer than in 1999.
  90. Sheehan, W., Boudreau, J., Manara, A., 2011, MmSAI, 82, 358, A figure in the carpet: Giovanni Schiaparelli's classic observations of Mercury reconsidered in the light of modern CCD images
    Though best known for his observations of Mars, Giovanni Virginio Schiaparelli also undertook a prolonged series of observations of Mercury leading to a rotation period for the planet that was repeatedly confirmed by later astronomers and would remain the standard for almost seven decades. In 1965, his result was shown to be mistaken. This study of Schiaparelli's drawings and notes in his observing log books in the light of CCD images allows a comprehensive understanding of how Schiaparelli reached the conclusions he did and provides insights into the difficulties of planetary studies in the visual era.
  91. 90 publications and 8325 citations in 2011.

90 publications and 8325 citations total.