Externally Polluted White Dwarfs with Dust Disks
نویسندگان
چکیده
منابع مشابه
Carbon Deficiency in Externally-polluted White Dwarfs: Evidence for Accretion of Asteroids
Existing determinations show that n(C)/n(Fe) is more than a factor of 10 below solar in the atmospheres of three white dwarfs that appear to be externallypolluted. These results are not easily explained if the stars have accreted interstellar matter, and we re-interpret these measurements as evidence that these stars have accreted asteroids with a chondritic composition. Subject headings: plane...
متن کاملX-ray and Infrared Observations of Two Externally-polluted White Dwarfs
With XMM-Newton and the Spitzer Space Telescope, we obtain upper bounds to the X-ray fluxes from G29-38 and GD 362, and the 70 μm flux from G29-38. These data provide indirect evidence that G29-38 is accreting from a tidally disrupted asteroid: it is neither accreting large amounts of hydrogen and helium nor is its surrounding dusty disk being replenished from a reservoir of cold grains experie...
متن کاملDisks and Planets around Massive White Dwarfs
We predict the existence of dusty disks and possibly CO planets around massive white dwarfs. We show that the thermal emission from these disks should be detectable in the infrared. The planets may also be detectable either by direct IR imaging, spectroscopy, or using the pulsations of the white dwarfs. Subject headings: white dwarfs—stars: planetary systems—accretion disks
متن کاملDebris Disks Around White Dwarfs: The Daz Connection
We present near-infrared spectroscopic observations of 20 previously known DAZ white dwarfs obtained at the NASA Infrared Telescope Facility. Two of these white dwarfs (G29-38 and GD 362) are known to display significant K-band excesses due to circumstellar debris disks. Here we report the discovery of excess K-band radiation from another DAZ white dwarf, WD 0408 041 (GD 56). Using spectroscopi...
متن کاملSpectral modeling of gaseous metal disks around DAZ white dwarfs
We report on our attempt for the first non-LTE modeling of gaseous metal disks around single DAZ white dwarfs recently discovered by Gänsicke et al. and thought to originate from a disrupted asteroid. We assume a Keplerian rotating viscous disk ring composed of calcium and hydrogen and compute the detailed vertical structure and emergent spectrum. We find that the observed infrared Ca ii emissi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2007
ISSN: 0004-637X,1538-4357
DOI: 10.1086/518767