Two New Variable Hot DQ Stars

Abstract

We have discovered periodic variations in the light curves of two hot DQ stars from the Sloan Digital Sky Survey, SDSS J220029.08-074121.5 and SDSS J234843.30-094245.3. These are the second and third variables detected among the hot DQs and confirm the existence of a new class of variable white dwarf stars. The amplitudes of the variations are one half as large as those detected in the first discovered variable, SDSS J142625.71+575218.3, and required high signal-to-noise photometry to detect. The pulse shapes of the stars are not like those of known white dwarf pulsators but are similar to the first hot DQ variable, SDSS J142625.71+575218.3.

Accepted for publication in ApJ Letters (14 pages, 5 figures, 2 tables)

References in corpus (6)

• Rare White dwarf stars with carbon atmospheres
• Gravity-Modes in ZZ Ceti Stars: I.Quasiadiabatic Analysis of Overstability
• Hot DQ White Dwarfs: Something Different
• SDSS J142625.71+575218.3, a Prototype for a New Class of Variable White Dwarf
• SDSS J142625.71+575218.3: The First Pulsating White Dwarf with a Large Detectable Magnetic Field
• Might Carbon-Atmosphere White Dwarfs Harbour a New Type of Pulsating Star?

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• Taking Advantage of the COS Time-Tag Capability: Observations of Pulsating Hot DQ White Dwarfs and Discovery of a New One
• SDSS J000555.90-100213.5: a hot, magnetic carbon-atmosphere WD rotating with a 2.1 day period
• Photometric variability in a warm, strongly magnetic DQ white dwarf, SDSS J103655.39+652252.2
• A New Small-Amplitude Variable Hot DQ White Dwarf
• Stark Broadening of Carbon and Oxygen Lines in Hot DQ White Dwarf Stars: Recent Results and Applications
• Follow-up Studies of the Pulsating Magnetic White Dwarf SDSS J142625.71+575218.3
• Follow-up Observations of the Second and Third Known Pulsating Hot DQ White Dwarfs
• Hot C-rich white dwarfs: testing the DB-DQ transition through pulsations
• The OmegaWhite Survey for Short-Period Variable Stars IV: Discovery of the warm DQ white dwarf OW J175358.85-310728.9