Born 1943, London, United Kingdom
        Married
        U.S. citizen

1955-1962: Student at Emanuel School, London

1962-1965: University College London (B.Sc in astronomy)

1965-1967: Associate, European Space Research Organization, Observatoire de Meudon

1967-1970: Research Assistant, Lunar Group, Department of Astronomy, University College London

1970-1971: Lecturer, Department of Astronomy, University College London

1971-1973: Fellow, European Space Research Organization, Observatoire de Meudon

1973: D. es Sci. (Doctorat de l'Universite), Universite de Paris 6 (astrophysics)

1973-1979: Astronomer, Lowell Observatory

1979-present: Senior Astronomer, Lowell Observatory

2000-2003: President, Commission 20 (Positions and Motions of Minor Planets, Comets and Satellites) of the International Astronomical Union

2003-2006: Vice President, Division III (Planetary System Sciences) of the International Astronomical Union

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PRINCIPAL PUBLICATIONS

Dollfus, A., and Bowell, E. (1971). Polarimetric properties of the lunar surface and its interpretation, Part I. Observations. Astron. Astrophys. 10, 29-53.

Bowell, E. (1973). Analyse polarim\'etrique de la Lune, des roches terrestres et des \'echantillons lunaires avec application aux astero\"\i des et satellites [in French], 114pp., D. \`es Sci. thesis, University of Paris 6.

Bowell, E., and Zellner, B. (1974). Polarizations of asteroids and satellites. In Planets, Stars, and Nebulae Studied with Photopolarimetry (T. Gehrels, ed.), pp. 381-404. University of Arizona Press, Tucson.

Zellner, B., and Bowell, E. (1977). Asteroid compositional types and their distributions. In Comets, Asteroids, Meteorites - Interrelations, Evolution and Origins (A. H. Delsemme, ed.), pp. 185-197. University of Toledo, Toledo, Ohio.

Bowell, E., Chapman, C. R., Gradie, J. C., Morrison, D., and Zellner, B. (1978). Taxonomy of asteroids. Icarus 35, 313-335.

Bowell, E., Gehrels, T., and Zellner, B. (1979) Magnitudes, colors, types and adopted diameters of the asteroids. In Asteroids (T. Gehrels, ed.), pp. 1108-1129. University of Arizona Press, Tucson.

Bowell, E., and Lumme, K. (1979). Colorimetry and magnitudes of asteroids. In Asteroids (T. Gehrels, ed.), pp. 132-169. University of Arizona Press, Tucson.

Lumme, K., and Bowell, E. (1981). Radiative transfer in the surfaces of atmosphereless bodies. I. Theory. Astron. J. 86, 1694-1704.

Lumme, K., and Bowell, E. (1981). Radiative transfer in the surfaces of atmosphereless bodies. II. Interpretation of phase curves. Astron. J. 86, 1705-1712.

Bowell, E., Wasserman, L. H., Baum, W. A., Millis, R. L., and Lumme, K. (1984). Occultations of stars and radio sources by comets: predictions and observing prospects. In Cometary Astrometry (D. K. Yeomans, R. M. West, R. S. Harrington, and B. G. Marsden, eds.), pp. 105-122. JPL Publ. 84-82.5.

Lumme, K., and Bowell, E. (1985). Photometric properties of zodiacal light particles. Icarus, 62, 54-71.

Bus, S. J., Bowell, E., Harris, A. W., and Hewitt, A. V. (1989). 2060 Chiron: CCD and electronographic photometry. Icarus 77, 223-238.

Karttunen, H., and Bowell, E. (1989). Modelling asteroid brightness variations. II. The uninterpretability of light curves and phase curves. Astron. Astrophys.
208, 320-326.

Bowell, E., Marsden, B. G., and Chernykh, N. S. (1989). Discovery and follow up of asteroids. In Asteroids II (R. P. Binzel, T. Gehrels, and M. S. Matthews, eds.), pp. 21-38. University of Arizona Press, Tucson.

Bowell, E., Hapke, B., Domingue, D., Lumme, K., Peltoniemi, J., and Harris, A. W. (1989). Application of photometric models to asteroids. In  Asteroids II (R. P. Binzel, T. Gehrels, and M. S. Matthews, eds.), pp. 524-556. University of Arizona Press, Tucson.

Lumme, K., Karttunen, H., and Bowell, E. (1990). A spherical harmonics method for asteroid pole determination. Astron. Astrophys. 229, 228-239.

Bus, S. J., A'Hearn, M. F., Schleicher, D. G., and Bowell, E. (1991). Detection of CN emission from (2060) Chiron. Science 251, 774-777.

Morrison, D., Binzel, R. P., Bowell, E., Chapman, C. R., Friedman, L., Gehrels, T., Helin, E. F., Marsden, B. G., Maury, A., Morgan, T. H., Muinonen, K., Ostro, S. J., Pike, J., Rahe, J. H., Rajamohan, R., Rather, J. D. G., Russell, K. S., Shoemaker, E. M., Sokolsky, A., Steel, D. I., Tholen, D. J., Veverka, J., Vilas, F., and Yeomans, D. K. (1992). The Spaceguard Survey: Report of the NASA International Near-Earth-Object Detection Workshop, NASA, Washington, D.C.

Kaasalainen, M., Lamberg, L., Lumme, K., and Bowell. (1992). Interpretation of lightcurves of atmosphereless bodies. I. General theory and new inversion schemes. Astron. Astrophys. 259, 318-332.

Binzel, R. P., Xu, S., Bus, S. J., and Bowell, E. (1992). Origins for near-Earth asteroids. Science 257, 779-780.

Binzel, R. P., Xu, S., Bus, S. J., and Bowell, E. (1992). Small main-belt asteroid lightcurve survey. Icarus 99, 225-237.

Muinonen, K., and Bowell, E. (1993). Asteroid orbit determination using Bayesian probabilities. Icarus 104, 255-279.

Bowell, E., and Muinonen, K. (1994). Earth-crossing asteroids and comets: Groundbased search strategies. In Hazards Due to Comets and Asteroids (T. Gehrels, ed.), pp.149-197. University of Arizona Press, Tucson.

Rabinowitz, D. L., Bowell, E., Muinonen, K., and Shoemaker, E. M. (1994). The population of Earth-crossing asteroids. In Hazards Due to Comets and Asteroids (T. Gehrels, ed.), pp.285-312. University of Arizona Press, Tucson.

Mikkola, S., Innanen, K., Muinonen, K., and Bowell, E. (1994). A preliminary analysis of the orbit of the Mars Trojan asteroid (5261) Eureka. Cel. Mech. and Dynam. Astron. 58, 53-64.

Muinonen, K., Bowell, E., and Wasserman, L. H. (1994). Orbital uncertainties of single-apparition asteroids. Planet. Space Sci. 42, 307-313.

Muinonen, K., Bowell, E., and Wasserman, L. H. (1994). A public-domain asteroid orbit database. In Asteroids, Comets, Meteors 1993 (A. Milani et al., eds.), pp.477-481. Kluwer, Dordrecht.

Muinonen, K., Bowell, E., and Lumme, K. (1995). Interrelating asteroid size, albedo, and magnitude distributions. Astron. Astrophys. 293, 948-952.

Howell, S. B., Koehn, B. W., Bowell, E., and Hoffman, M. (1996). Detection and measurement of poorly sampled point sources imaged with 2-D arrays. Astron. J. 112, 1302-1311.

Muinonen, K., Milani, A., and Bowell, E. (1997). Determination of initial eigenorbits for asteroids. In Dynamics and Astrmetry of Natural and Artificial Celestial Bodies (I. M. Wytrzyszczak, J. H. Lieske, and R. A. Feldman, eds.), pp. 191-198. Kluwer Academic Publishers.

Bus, S. J., A'Hearn, M. F., Bowell, E., and Stern, S. A. (2001). Chiron: Evidence for activity near perihelion. Icarus 150, 94-103.

Virtanen, J. Muinonen, K., and Bowell, E. (2001). Statistical ranging of asteroid orbits. Icarus 154, 412-431.

Bowell, E., Virtanen, J., Muinonen, K., and Boattini, A. (2002). Asteroid orbit computation. In Asteroids III (W. F. Bottke Jr., A. Cellino, P. Paolicchi, and R. P. Binzel, eds.), pp. 27-43. The University of Arizona Press, Tucson.

Virtanen, J., Tancredi, G., Muinonen, K., and Bowell, E. (2003). Orbit computation for transneptunian objects. Icarus 161, 419-430.

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BIOGRAPHICAL NOTES

My interest in astronomy was prompted, when I was a teenager in London, by the gift of a telescope from my father. Surveying the night sky, even in conditions of poor transparency, soon convinced me of two things: Being an astronomer must be fun because one could stay up late at night and therefore wouldn't have to get up early in the morning; planets are more interesting than stars because they exhibit more variation and because they move in predictable ways.

The path to actually becoming an astronomer started with the realization that I was not talented enough to pursue my first two penchants: to become a musician or a writer. In high school, I absorbed as much astronomical literature as I could, often quite technical stuff, and then managed to get accepted at University College London, one of just a handful of institutions in the U.K. then offering honors degrees in astronomy. My predilection for planetary science was strengthened during the three years getting a B.Sc. I deferred study for a Ph.D. in London for lack of money, but instead, in 1965 got a generous stipend from the European Space Research Organisation (now the European Space Agency) to work with Dr. Audouin Dollfus at Meudon Observatory, a branch of Paris Observatory, on the polarization properties of the lunar surface. Our work together was a small cog in the vast mechinery of the Apollo missions, and was aimed at answering some of the questions about what it would be like to stand on the Moon, and especially what the texture of the lunar soil would be. We got it just about right: one would not sink out of sight in fine powder, but would leave detailed footprints in the surface of finely pulverized rocks. During that time, I had my first chance to make extensive and systematic telescopic observations, mainly of the Moon and Mars. (Also, I was learning to test the great chef Anthelme Brillat-Savarin's dictum that "The discovery of a new culinary dish does more for humanity than the discovery of a star.")

When, after two years, my ESRO stipend expired, I returned to London in 1967 to join a newly formed "Lunar Group", headed by Dr. Gilbert Fielder at University College London Observatory. Here I was put in charge of a project to determine the thermal conductivity of lunar soil and rocks (how fast does heat diffuse in and out of lunar materials?). This was a tough assignment for me, not being a very good experimental physicist, and I didn't succeed very well, although it was quite a thrill to be able to handle sizeable chunks of rock from the Moon.

Then, in 1971, after doing some university lecturing and teaching of popular astronomy, I returned to Meudon to continue work on polarization. That year was one of the best perihelic oppositions of Mars, and I spent a lot of time, mainly at Pic du Midi Observatory in the Pyrenees, securing planetary images and making polarization measurements of Mars. It was gratifying to be able to document the Martian dust storm of that year using the two complementary techniques. Shortly after publishing the lunar polarization studies and some of the work on Mars, I made the acquaintance of Dr. Benjamin Zellner of the University of Arizona, who was visiting Meudon on sabbatical. He enthused me with the idea of studying asteroids; after all, there are thousands of them, the biggest in the size range of our Moon, and I could go on making polarization measurements for a very long time without exhausting the subject.

During 1973, my last year in Meudon, I realized I had better get a doctorate if I wanted to continue research in astronomy. The University of Paris had a program that was tailor-made for me: all I had to do was submit a thesis that described my previous research and have it judged by a panel appointed partly by the University, partly by me. The judgment would, of course be to the high standards expected of a Ph.D. student. I wrote the thesis, got some help getting it translated into French, defended it, and got my accreditation as a Docteur de l'Universite in about two months.

Then, out of the blue, came an irresistible job offer: the chance to work at Lowell Observatory in Flagstaff, Arizona, on a permanent basis. The offer was made by Dr. William A. Baum, then Director of the Planetary Research Center at Lowell, who was engaged in a synoptic photographic study of some of the planets. Being interested in Mars and Venus, both of which have intriguing polarimetric properties, I jumped at the chance. However, I soon found myself drawn back to asteroids, and continued work on them with Ben Zellner. Ben and I formulated the idea that it would be valuable to measure the colors ("color indices") of several hundred asteroids as a quick way of getting compositionally diagnostic information on the main asteroid belt as a whole. Thus, I became an observational astronomer in earnest, for five years doing photometry of asteroids for several nights (weather permitting) each dark of the Moon, and amassing good data on more than 600 asteroids. Armed with these data, Zellner and I tried to map the compositional structure of the main belt, and showed that there were very striking patterns in it. Later, helped greatly by more experienced colleagues, I helped devise a taxonomy of asteroids; that is, to categorize them according to their compositional types as characterized by a number of parameters, including colors.

Another old interest of mine, studying the photometry of atmosphereless solar system bodies to infer the nature and texture of their surfaces, was reignited by meeting Dr. Kari Lumme of the University of Helsinki. Kari is a very capable theoretician but not at all an observer, and I am just the opposite, so we complemented each other as a team. Our work was mainly centered on asteroids, just because there are lots of them and because they display quite a bit of variety in how there surfaces scatter (reflect) light. Perhaps the most lasting aspect of this work was a method of computing the brightness of asteroids as their geometry with respect to the Earth and Sun changes. The so-called H,G system was adopted by the International Astronomical Union as a worldwide standard in 1985.

A little before the end of the taxonomy project, Lowell Observatory had acquired a PDS scanning microdensitometer, a device capable of scanning photographic plates in great detail. Realizing that the PDS could be used to do rather well-automated astrometry of asteroids, and remembering my frequent frustration at not being able to find asteroids at the telescope because of their poor orbits and ephemerides, I and colleague Dr. Lawrence Wasserman explored ways of doing the astrometry. But first, I had to have some plates, so I went out to the old 13-inch A. Lawrence Lowell refractor (the telescope Clyde Tombaugh had used to discover Pluto in 1930) to get some test exposures. Later, sitting down at a blink comparator and discovering an asteroid for the first time got me hooked. Thus started a major survey for asteroids that lasted from 1979 to 1988. Altogether, more than 600 of our asteroid discoveries were numbered, making our group, in its time, among the most prolific worldwide. Now, one of the real perks of discovering asteroids is eventually getting to name them, which is a unique distinction for celestial bodies of any kind (the International Star Register notwithstanding). It has given me great pleasure to name asteroids after scientific colleagues, some of my friends, and other entities of interest to me.

As a student in London I had developed software to compute 2-body and perturbed orbit solutions for asteroids. The problem is, given the position and motion of an asteroid, and given the gravitational pulls on it from the Sun, the planets, and other asteroids, where will it move next? It's the n-body problem, but in a form that is calculable using numerical integration based on finite differences. If one just takes tiny steps, so the forces pulling the asteroid don't change very much, one can compute its position in space, and therefore from the Earth, to great accuracy. The immediate practical application of my software was to predict where asteroids would be visible against the starry background. But for a long time there was a niggling problem that no one seemed to have worked on in any detail: How could one predict the future positions of an asteroid when its orbit is poorly known? A frequently occurring example is the case of a newly discovered asteroid, when all one knows is its direction and rate of motion on the sky. It was Kari Lumme who introduced me to a very skilled graduate student, Karri Muinonen, as a person who could help. Karri spent a couple of years at Lowell observatory as a post doc, during which time we developed a new method of orbit computation, based on Bayesian probabilities, which allowed for uncertainties in asteroids' orbital elements stemming from uncertainties in their measured positions on the sky and the lengths of their observed orbital arcs. The work has developed further after Karri returned to Helsinki and formed his own group of students. Most recently, we have worked together on an orbit-calculation method called statistical ranging, which is capable of yielding the entire family of orbits possible from a given set of astrometric observations. One can thus use statistical ranging to predict where in the sky a given asteroid can possibly be, even if it seems hopelessly lost.

Thus it is the discovery, observation, follow-up, and orbit computation of asteroids that intrigue me most, and to this end I have been trying to convince my colleagues that, although we know with great accuracy the orbits and locations of about 100,000 asteroids, we need to know about many times more. Time and again in planetary science, one can point to the steady accumulation of data as being a prerequisite of deeper knowledge. This is especially true of asteroid science, where we cannot yet fully characterize the structure of the main belt, and where our knowledge of so-called Hirayama families, groups of asteroids that resulted long ago from the collisional breakup of a parent asteroids, can be much further developed. Bringing all these interests together has led me to work within the International Astronomical Union, the world body that oversees certain aspects of astronomy, including the cataloguing and naming of asteroids and comets. I have served as President of the IAU Commission that deals with the motions and orbits of asteroids, comets, and natural satellites, and am currectly Vice President of one of 12 IAU Divisions.

A decade ago, I embarked on an ambitious discovery project, one that uses leading-edge technology to search large areas of sky. I am trying to understand the group of objects known as near-Earth asteroids (NEAs), particularly those that could collide with Earth and thus be hazardous to mankind. Aside from studies of the Sun (Is its brightness varying? Could we fry or freeze? When is the next major flare going to black out radio communication on Earth?), I can think of no more practical use of astronomy. And finding and charting NEAs could be even more important than solar work, because for once there is something we can do to mitigate the hazard: using current or developable technology, NEAs can either be diverted from a collision course with Earth or they can blown apart. Right now, we only know of about 1,500 asteroids (some of them dead comets) whose orbital paths bring them inside the Earth's orbit, and thus could strike the Earth, though no known NEA will do so in the next century. In my opinion, we must discover many more so we have some chance to make a realistic assessment of the hazard of NEAs.

As a start along this path, I am directing the Lowell Observatory Near-Earth-Object Search. LONEOS uses a 59-cm Schmidt telescope to discover asteroids and comets that can approach the Earth (collectively, Near-Earth Objects or NEOs). Nightly observing started in March 1998, and to date (Januart 2004) my group has discovered 177 near-Earth asteroids and 18 comets. We have submitted more than 2 million observations of asteroids and comets to the Minor Planet Center, the worldwide clearinghouse for such data. In terms of the discovery of larger NEOs, our search effort has, over the past years, been second or third worldwide. We are currently searching the sky at a steady monthly rate of about 12,000 sq. deg. This is about a quarter of the celestial sphere and more than half of the dark sky visible from Flagstaff. Our limiting magnitude is about V = 19.0 for moving objects, which is 100,000 times fainter than the naked eye can see. We are detecting an average of 5 NEOs per night with our alomost completely automated system. In 2003 alone, we found 54 NEAs, three of them of particular note: 2003 EH1, perhaps 3 km in diameter, is almost certainly the parent body of the Quandrantid meteor shower; 2003 SQ222 made the closest well-documented approach of any known asteroid (1/5 the distance of the Moon); and we rediscovered 1937 UB (Hermes), the first NEA ever seen, after it had been lost for 66 years.

Lowell Observatory has recently announced a collaboration with Discovery Communications, Inc., to build a 4.3-meter wide-field telescope. The CCD camera planned for it should enable us to discover NEAs at the rate of 20 to 50/hour---about 10 times the current worldwide rate. The new telescope is set to start operation in 2008. I and my LONEOS colleague Bruce Koehn, are starting to address the problems that will be raised by scaling up our observing operations by two orders of magnitude.