Faint Debris Disks around Bright Stars using WISE

Wednesday, 29 June 2016 8 a.m. — 9 a.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
RAHUL PATEL (Infrared Prcessing and Analysis Center, California Institute of Technology and NOAO South Visiting Astronomer)

Non-primordial, circumstellar dust around main-sequence stars is created from the destructive collisional cascades between planetesimals, comets and asteroids. This debris, which forms circumstellar disks or rings, is a signpost for planetary systems, as the collisions must be induced by larger bodies in the system. The majority of debris disks detected to date are cold disks, analogous to the Edgeworth-Kuiper belt in our Solar System, and identified from their unresolved thermal infrared excess flux at far-IR wavelengths. However, dust in regions analogous to the terrestrial planet zone and asteroid belt is identified from its mid-IR excess flux, and is significant as it traces material related to terrestrial planet formation. This dust is warmer and much more difficult to detect. Consequently, the number of cold dust detections far outweighs the number of warm dust detections. 

To search for previously undetected warm debris disks, I, along with my collaborators, use data from the WISE All-Sky survey, which presents an opportunity to extend the population of faint disks to flux levels 100x fainter than disks detected by IRAS. In this talk, I will discuss our contribution to the census of warm debris disks with this new set of reliable detections from WISE, and the precise calibration of the WISE data to identify faint levels of dust around bright stars within the solar neighborhood. These new nearby excess hosts are optimal targets for direct imaging campaigns to characterize the disk morphology and to provide a larger sample of well characterized disks with which to understand the overall exoplanetary system architecture.