SDSS J142625.71+575218.3, a Prototype for a New Class of Variable White Dwarf

TL;DR

This paper reports the discovery of SDSS J142625.71+575218.3 as the first candidate of a new class of pulsating white dwarfs, the DQVs, characterized by unique pulsation and pulse shape features.

Contribution

It identifies SDSS J142625.71+575218.3 as the first member of a new class of pulsating white dwarfs, the DQVs, with distinctive pulsation properties and potential links to AM CVn stars.

Findings

Star shows variability at 417.7 s and 208.8 s.

Pulse shape differs from other white dwarf variables.

Potential similarity to AM CVn stars.

Abstract

We present the results of a search for pulsations in six of the recently discovered carbon-atmosphere white dwarf ("hot DQ") stars. Based on our theoretical calculations, the star SDSS J142625.71+575218.3 is the only object expected to pulsate. We observe this star to be variable, with significant power at 417.7 s and 208.8 s (first harmonic), making it a strong candidate as the first member of a new class of pulsating white dwarf stars, the DQVs. Its folded pulse shape, however, is quite different from that of other white dwarf variables, and shows similarities with that of the cataclysmic variable AM CVn, raising the possibility that this star may be a carbon-transferring analog of AM CVn stars. In either case, these observations represent the discovery of a new and exciting class of object.