Discovery of a New Massive ZZ Ceti Star

Abstract

Massive pulsating white dwarf stars are extremely rare, because they are the final product of intermediate-mass stars, which are less common than low-mass stars. Additionally, their small size makes them fainter than the normal-mass white dwarf stars (∼0.6 M ⊙). Our motivation to look for this type of variable is to be able to study in detail their internal structure and therefore derive properties for the outcome of the evolution of intermediate mass stars, below 10 M ⊙. Using the 2.1 m Otto Struve Telescope at McDonald Observatory, we report on the discovery of a new massive pulsating white dwarf star. These stars might be massive enough that their cores have a significant crystallized portion, up to about 50%. A detailed asteroseismic study of these stars will provide important constrains on intermediate-mass stellar evolution, and the opportunity to study solid state physics at extreme conditions.