THE WIRED SURVEY. IV. NEW DUST DISKS FROM THE McCOOK & SION WHITE DWARF CATALOG

Abstract

We have compiled photometric data from the Wide-field Infrared Survey Explorer All Sky Survey and other archival sources for the more than 2200 objects in the original McCook & Sion Catalog of Spectroscopically Identified White Dwarfs. We applied color-selection criteria to identify 28 targets whose infrared spectral energy distributions depart from the expectation for the white dwarf photosphere alone. Seven of these are previously known white dwarfs with circumstellar dust disks, five are known central stars of planetary nebulae, and six were excluded for being known binaries or having possible contamination of their infrared photometry. We fit white dwarf models to the spectral energy distributions of the remaining ten targets, and find seven new candidates with infrared excess suggesting the presence of a circumstellar dust disk. We compare the model dust disk properties for these new candidates with a comprehensive compilation of previously published parameters for known white dwarfs with dust disks. It is possible that the current census of white dwarfs with dust disks that produce an excess detectable at K-band and shorter wavelengths is close to complete for the entire sample of known WDs to the detection limits of existing near-IR all-sky surveys. The white dwarf dust disk candidates now being found using longer wavelength infrared data are drawn from a previously underrepresented region of parameter space, in which the dust disks are overall cooler, narrower in radial extent, and/or contain fewer emitting grains.

Infrared observations of white dwarfs and the implications for the accretion of dusty planetary material

“…In addition to which, the temperatures for the observed dust discs are generally significantly hotter than 700K (e.g. Hoard et al 2013). We, therefore, conclude that the absence of infrared excesses is unlikely to be explained by the discs being cool.…”

RADIO-WEAK BL LAC OBJECTS IN THEFERMIERA

“…This catalog has been also used to search for dusty disks around WDs (Hoard et al 2013) using WISE observations. However in this sample the number of sources detected at 3.4µm, 4.6µm and 12µm for which is possible to built the mid-IR colors is only 91.…”

Remnant planetary systems around bright white dwarfs

“…We find that WD 0420+520 is surrounded by a thin, 0.05 R wide, dusty disc. This object was first identified as a candidate WD+disc system using WISE by Hoard et al (2013) and was recently found to have Ca absorption lines in its Keck+HIRES spectrum (Debes, private communication). There is a blended source in the IRAC Ch 1 photometry, but is cleanly subtracted (Fig.…”