A Spitzer Space Telescope Study of the Debris Disks around four SDSS White Dwarfs

Abstract

We present Spitzer Space Telescope data of four isolated white dwarfs that were previously known to harbor circumstellar gaseous disks. IRAC photometry shows a significant infrared excess in all of the systems, SDSS0738+1835, SDSS0845+2257, SDSS1043+0855 and SDSS1617+1620, indicative of a dusty extension to those disks. The 4.5-micron excesses seen in SDSS0738, SDSS0845, and SDSS1617 are 7.5, 5.7 and 4.5 times the white dwarf contribution, respectively. In contrast, in SDSS1043, the measured flux density at 4.5 microns is only 1.7 times the white dwarf contribution. We compare the measured IR excesses in the systems to models of geometrically thin, optically thick disks, and find that we are able to match the measured SEDs to within 3 sigma of the uncertainties, although disks with unfeasibly hot inner dust temperatures generally provide a better fit than those below the dust sublimation temperature. Possible explanations for the dearth of dust around SDSS1043+0855 are briefly discussed. Including our previous study of SDSS1228+1040, all five white dwarfs with gaseous debris disks have significant amounts of dust around them. It is evident that gas and dust can coexist around these relatively warm, relatively young white dwarfs.

20 pages, including 4 figures. Accepted to ApJ

References in corpus (11)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• A gaseous metal disk around a white dwarf
• The Chemical Composition of an Extrasolar Minor Planet
• Pollution of single white dwarfs by accretion of many small asteroids
• Externally-polluted white dwarfs with dust disks
• Debris Disks Around White Dwarfs: The DAZ Connection
• Constraints on the Lifetimes of Disks Resulting from Tidally Destroyed Rocky Planetary Bodies
• SDSSJ104341.53+085558.2: A second white dwarf with a gaseous debris disc
• Rocky Extrasolar Planetary Compositions Derived from Externally-Polluted White Dwarfs
• Spitzer Observations of White Dwarfs: the Missing Planetary Debris Around DZ Stars
• The Discovery of a Debris Disk Around the DAV White Dwarf PG 1541+651

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• Variable Emission from a Gaseous Disc around a Metal-Polluted White Dwarf
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• The Drop during Less than 300 days of a Dusty White Dwarf's Infrared Luminosity
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• The WIRED Survey. IV. New Dust Disks from the McCook & Sion White Dwarf Catalog
• Accretion from debris disks onto white dwarfs : Fingering (thermohaline) instability and derived accretion rates
• Transient outburst events from tidally disrupted asteroids near white dwarfs
• White dwarf pollution by hydrated planetary remnants: Hydrogen and Metals in WD J204713.76-125908.9
• Serendipitous Discovery of Nine White Dwarfs With Gaseous Debris Disks
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• Another one grinds the dust: Variability of the planetary debris disc at the white dwarf SDSS J104341.53+085558.2
• The dust never settles: collisional production of gas and dust in evolved planetary systems
• Evidence for an Anhydrous Carbonaceous Extrasolar Minor Planet
• Extrasolar Refractory-Dominated Planetesimals: an Assessment
• Fast and Slow Precession of Gaseous Debris Disks Around Planet-Accreting White Dwarfs
• ALMA and Herschel Observations of the Prototype Dusty and Polluted White Dwarf G29-38
• Dusty Disks Around Central Stars of Planetary Nebulae
• Near-infrared variability in dusty white dwarfs: tracing the accretion of planetary material
• Multi-wavelength observations of the EUV variable metal-rich white dwarf GD 394
• Line Profiles of the Calcium I Resonance Line in Cool Metal-polluted White Dwarfs
• UV-excess sources with a red/IR-counterpart: low-mass companions, debris disks and QSO selection
• Non-LTE spectral models for the gaseous debris-disk component of Ton 345
• The Elemental Compositions of Extrasolar Planetesimals
• Gaia white dwarfs with infrared excess I. The 100 pc catalogue