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| Paper: |
The Frequency of Debris Disks at White Dwarfs |
| Volume: |
469, 18th European White Dwarf Workshop (EUROWD12) |
| Page: |
457 |
| Authors: |
Barber, S. D.; Patterson, A. J.; Kilic, M.; Leggett, S. K.; Dufour, P.; Bloom, J. S.; Starr, D. L. |
| Abstract: |
We present near- and mid-infrared photometry and spectroscopy from PAIRITEL, IRTF, and Spitzer of a metallicity-unbiased sample of 117 cool, hydrogen-atmosphere white dwarfs from the Palomar-Green survey and find five with excess radiation in the infrared, translating to a 4.3-1.2+2.2 % frequency of debris disks. This is slightly higher than, but consistent with the results of previous surveys. Using an initial-final mass relation, we apply this result to the progenitor stars of our sample and conclude that 1–7M☉ stars have at least a 4.3% chance of hosting planets; an indirect probe of the intermediate-mass regime eluding conventional exoplanetary detection methods. Alternatively, we interpret this result as a limit on accretion timescales as a fraction of white dwarf cooling ages; white dwarfs accrete debris from several generations of disks for ∼10Myr. The average total mass accreted by these stars ranges from that of 200km asteroids to Ceres-sized objects, indicating that white dwarfs accrete moons and dwarf planets as well as Solar System asteroid analogues. |
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