The new class of dusty DAZ white dwarfs
Abstract
Our mid-infrared survey of 124 white dwarfs with the Spitzer Space Telescope and the IRAC imager has revealed an infrared excess associated with the white dwarf WD 2115-560 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 discuss these four objects as a class, which we abbreviate "DAZd," where the "d" stands for "dust." Using an optically thick, geometrically thin disk model analogous to Saturn's rings, we find that the inner disk edges are at ≳ 0.1-0.2 R⊙ and that the outer disk edges are ~0.3-0.6 R⊙. This model naturally explains the accretion rates and lifetimes of the detected WD disks and the accretion rates inferred from photospheric metal abundances.
Additional Information
© 2007 The American Astronomical Society. Received 2006 October 9; accepted 2007 March 12. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Support for this work was provided by NASA through award project NBR 1269551 issued by JPL/Caltech to the University of Texas.Attached Files
Published - HIPapj07.pdf
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Additional details
- Eprint ID
- 14774
- Resolver ID
- CaltechAUTHORS:20090803-150955335
- NBR 1269551
- NASA
- Created
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2009-08-26Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field