Poster Abstracts

Name/Affiliation:  Rahul Patel (Stony Brook University)

Title:  Sensitive Identication of Warm Debris Disks in the Solar Neighborhood through Precise Calibration of Saturated WISE Photometry

The WISE All-Sky Survey Catalog presents an opportunity to expand the number of detections of warm (>100K) circumstellar dust in asteroid belt-analog regions. Not only would this increase in detections be useful to statistically constrain the occurrence rate of such dusty systems but imaging campaigns can use any targets in the solar neighborhood (<75 pc) as optimal targets to spatially characterize the morphology of the dust population. However, WISE bands saturate at relatively bright magnitudes, effectively removing bright stars from WISE excess searches. In this study we identify 220 Hipparcos stars within 75 pc with mid-infrared excesses arising from warm optically thin circumstellar dust at the W3 (12 um) and W4 (22 um) bands. For the first time, we are able to detect small excesses even around bright solar neighborhood stars by deriving and applying corrections to the fluxes of saturated stars in WISE. For optimal sensitivity, we use the stars’ contemporaneously measured shorter-wavelength fluxes at W1 (3.4 um) and W2 (4.6 um) to identify excesses at W3 and W4. These systematic corrections, together with careful inspection of other possible sources of contamination (e.g., interstellar cirrus, unresolved companions, scattered moonlight), enable us to increase by 45% the number of stars with warm dusty excesses within 75 pc of the Sun, even in the light of several recent studies on WISE. Our findings include five new stars with tenuous but significant W3 excesses, adding new members to the small population of known exozodi within 75 pc. Altogether, we have expanded the number of known debris disks (with excess at any wavelength) within 75 pc of the Sun by 29%. As a result of our WISE study, the number of debris disks with known 10–30um excesses within 75 pc (379) has now surpassed the number of disks with known >30um excesses (289, with 171 in common), even if the latter have been found to have a higher occurrence.