منابع مشابه
The New Class of Dusty Daz White Dwarfs
Our mid-infrared survey of 124 white dwarfs with the Spitzer Space Telescope and the IRAC imager has revealed an infrared excess associatedwith thewhite dwarf WD2115 560 naturally explained by circumstellar dust. This object is the fourth white dwarf observed to have circumstellar dust. All four are DAZ white dwarfs, i.e., they have both photospheric Balmer lines and photospheric metal lines.We...
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 کاملNew Spectral Analyses of Pre-white Dwarfs
The very hot, H-deecient PG 1159 stars are found in the post-AGB region of the Hertzsprung-Russell diagram. Most likely the \born-again" post-AGB scenario is valid for their evolution. It predicts a nal He-ash which brings back the star to the AGB, followed by a second (He burning) descent from the AGB where a superwind may take oo the entire H-rich and most of the He-rich envelope and lay bare...
متن کاملDegenerates with Dusty Disks: White Dwarfs and Cataclysmic Variables in the Infrared
Recent infrared observations, particularly from the Spitzer Space Telescope andWidefield Infrared Survey Explorer, of white dwarfs, cataclysmic variables and other interacting compact binaries, have revealed the presence of dust in many systems. I briefly review the discovery and observational properties of dust around white dwarfs and cataclysmic variables.
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2007
ISSN: 0004-637X,1538-4357
DOI: 10.1086/518108