The Frequency of Debris Disks at White Dwarfs

Дата и время публикации : 2012-09-14T20:00:29Z

Авторы публикации и институты :
Sara D. Barber
Adam J. Patterson
Mukremin Kilic
S. K. Leggett
P. Dufour
J. S. Bloom
D. L. Starr

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: ApJ, in press
Первичная категория: astro-ph.GA

Все категории : astro-ph.GA, astro-ph.SR

Краткий обзор статьи: 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+2.7-1.2% 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 1-7Msol 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.

Category: Physics