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

摘要

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