A subtle IR excess associated with a young White Dwarf in the Edinburgh-Cape Blue Object Survey

Abstract

We report the discovery of a subtle infrared excess associated with the young white dwarf EC\,05365--4749 at 3.35 and 4.6\,$\mu$m. Follow-up spectroscopic observations are consistent with a hydrogen atmosphere white dwarf of effective temperature 22\,800\,K and log [\emph{g} (\,cm\,s${}^{-2}$) ] = 8.19. High resolution spectroscopy reveals atmospheric metal pollution with logarithmic abundances of [Mg/H] = --5.36 and [Ca/H] = --5.75, confirming the white dwarf is actively accreting from a metal-rich source with an intriguing abundance pattern. We find that the infrared excess is well modeled by a flat, opaque debris disk, though disk parameters are not well constrained by the small number of infrared excess points. We further demonstrate that relaxing the assumption of a circular dusty debris disk to include elliptical disks expands the widths of acceptable disks, adding an alternative interpretation to the subtle infrared excesses commonly observed around young white dwarfs.

Accepted to ApJ, 11 pages, 9 figures

References in corpus (10)

• The WFCAM Science Archive
• unWISE: unblurred coadds of the WISE imaging
• The VISTA Science Archive
• Formation of planetary debris discs around white dwarfs I: Tidal disruption of an extremely eccentric asteroid
• Externally-polluted white dwarfs with dust disks
• On the Spectral Evolution of Cool, Helium-Atmosphere White Dwarfs: Detailed Spectroscopic and Photometric Analysis of DZ Stars
• Debris Disks Around White Dwarfs: The DAZ Connection
• The frequency and infrared brightness of circumstellar discs at white dwarfs
• Scars of Intense Accretion Episodes at Metal-Rich White Dwarfs
• Evidence for an Anhydrous Carbonaceous Extrasolar Minor Planet

Cited by in corpus (6)

• Tidal disruption of planetary bodies by white dwarfs I: A hybrid SPH-analytical approach
• The frequency of gaseous debris discs around white dwarfs
• The dust never settles: collisional production of gas and dust in evolved planetary systems
• WIRED for EC: New White Dwarfs with $\text{WISE}$ Infrared Excesses and New Classification Schemes from the Edinburgh-Cape Blue Object Survey
• A DZ white dwarf with a 30 MG magnetic field
• The unstable fate of the planet orbiting the A-star in the HD 131399 triple stellar system