2007/06/27 by Pierre-Olivier Quirion, G. Fontaine, P. Brassard · 2 citations
Mathematics · Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Atomic physics #Diagram #Excited state #Galaxy #Hertzsprung–Russell diagram #Instability #Instability strip #Luminosity #Mathematics #Mechanics #Metallicity #Physics #Stars #Stellar evolution #Stellar, planetary, and galactic studies #Surface gravity #White dwarf
paper · doi:10.1086/513870
openalex publication_date 2007/06/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/11
We present the results of a detailed stability study of models of GW Vir pulsators. These are extremely hot, evolved, and compact stars that are on their way to the white dwarf cooling phase and that show multiperiodic luminosity variations due to gravity-mode pulsational instabilities. Our nonadiabatic survey confirms that cyclic ionization of carbon and oxygen is at the origin of the GW Vir phenomenon. We find that the extent of the instability domain in the log g-Teff plane is a strong function of the C and O content in the envelopes of these stars. Given that GW Vir stars show important variations in atmospheric composition from one object to another, this implies that the notion of a blue edge for the GW Vir instability domain is necessarily a fuzzy concept. We investigate the effects of varying the total mass, of adding hydrogen, and of changing the metallicity. We summarize our results in the form of extensive stability maps in the log g-Teff diagram and produce tables and graphs showing the expected ranges of excited periods under various conditions.