Might Carbon-Atmosphere White Dwarfs Harbour a New Type of Pulsating Star?

Abstract

In the light of the recent and unexpected discovery of a brand new type of white dwarfs, those with carbon-dominated atmospheres, we examine the asteroseismological potential of such stars. The motivation behind this is based on the observation that past models of carbon-atmosphere white dwarfs have partially ionized outer layers that bear strong resemblance with those responsible for mode excitation in models of pulsating DB (helium-atmosphere) and pulsating DA (hydrogen-atmosphere) white dwarfs. Our exciting main result is that, given the right location in parameter space, some carbon-atmosphere white dwarfs are predicted to show pulsational instability against gravity modes. We are eagerly waiting the results of observational searches for luminosity variations in these stars.

arXiv comment4-page letter + 4 figures

References in corpus (2)

• Rare White dwarf stars with carbon atmospheres
• Mapping the ZZ Ceti Instability Strip: Discovery of 6 New Pulsators

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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 J142625.71+575218.3: The First Pulsating White Dwarf with a Large Detectable Magnetic Field
• Photometric variability in a warm, strongly magnetic DQ white dwarf, SDSS J103655.39+652252.2
• A New Small-Amplitude Variable Hot DQ White Dwarf
• Two New Variable Hot DQ Stars
• 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
• A Progress Report on the Carbon Dominated Atmosphere White Dwarfs
• White Dwarf Variability with gPhoton: Pulsators