Spitzer IRAC Observations of White Dwarfs. I. Warm Dust at Metal-Rich Degenerates

Abstract

This paper presents the results of a Spitzer IRAC 3-8 micron photometric search for warm dust orbiting 17 nearby, metal-rich white dwarfs, 15 of which apparently have hydrogen dominated atmospheres (type DAZ). G166-58, G29-38, and GD 362 manifest excess emission in their IRAC fluxes and the latter two are known to harbor dust grains warm enough to radiate detectable emission at near-infrared wavelengths as short as 2 micron. Their IRAC fluxes display differences compatible with a relatively larger amount of cooler dust at GD 362. G166-58 is presently unique in that it appears to exhibit excess flux only at wavelengths longer than about 5 micron. Evidence is presented that this mid-infrared emission is most likely associated with the white dwarf, indicating that G166-58 bears circumstellar dust no warmer than T~400 K. The remaining 14 targets reveal no reliable mid-infrared excess, indicating the majority of DAZ stars do not have warm debris disks sufficiently opaque to be detected by IRAC.

Accepted to ApJ, 10 figures, 6 tables

References in corpus (12)

• The Fifth Data Release of the Sloan Digital Sky Survey
• Externally-polluted white dwarfs with dust disks
• Debris Disks Around White Dwarfs: The DAZ Connection
• Carbon Deficiency in Externally-Polluted White Dwarfs: Evidence for Accretion of Asteroids
• The New Class of Dusty DAZ White Dwarfs
• The accretion-diffusion scenario for metals in cool white dwarfs
• Infrared Emission from the Dusty Disk Orbiting GD 362, An Externally-Polluted White Dwarf
• A Spitzer White Dwarf Infrared Survey
• Hot DB White Dwarfs from the Sloan Digital Sky Survey
• IRS Spectra of Solar-Type Stars: \break A Search for Asteroid Belt Analogs
• Measuring M dwarf Winds with DAZ White Dwarfs
• Infrared Photometric Analysis of White Dwarfs from The Two Micron All Sky Survey and the Spitzer Space Telescope

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