Artículo
Pulsation properties of ultra-massive DA white dwarf stars with ONe cores
de Gerónimo, Francisco César
; Abadi, Diego Alejandro
; Althaus, Leandro Gabriel
; Wachlin, Felipe Carlos
; Camisassa, María Eugenia
Fecha de publicación:
01/2019
Editorial:
EDP Sciences
Revista:
Astronomy and Astrophysics
ISSN:
0004-6361
e-ISSN:
1432-0746
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Context. Ultra-massive hydrogen-rich white dwarf stars are expected to harbor oxygen/neon cores resulting from the progenitor evolution through the super-asymptotic giant branch phase. As evolution proceeds during the white dwarf cooling phase, a crystallization process resulting from Coulomb interactions in very dense plasmas is expected to occur, leading to the formation of a highly crystallized core. In particular, pulsating ultra-massive white dwarfs offer a unique opportunity to infer and test the occurrence of crystallization in white dwarf interiors as well as physical processes related with dense plasmas. Aims. We aim to assess the adiabatic pulsation properties of ultra-massive hydrogen-rich white dwarfs with oxygen/neon cores. Methods. We studied the pulsation properties of ultra-massive hydrogen-rich white dwarf stars with oxygen/neon cores. We employed a new set of ultra-massive white dwarf evolutionary sequences of models with stellar masses in the range 1.10 ≤ M?/M ≤ 1.29 computed by taking into account the complete evolution of the progenitor stars and the white dwarf stage. During the white dwarf cooling phase, we considered element diffusion. When crystallization set on in our models, we took into account latent heat release and also the expected changes in the core chemical composition that are due to phase separation according to a phase diagram suitable for oxygen and neon plasmas. We computed nonradial pulsation g-modes of our sequences of models at the ZZ Ceti phase by taking into account a solid core. We explored the impact of crystallization on their pulsation properties, in particular, the structure of the period spectrum and the distribution of the period spacings. Results. We find that it would be possible, in principle, to discern whether a white dwarf has a nucleus made of carbon and oxygen or a nucleus of oxygen and neon by studying the spacing between periods. Conclusions. The features found in the period-spacing diagrams could be used as a seismological tool to discern the core composition of ultra-massive ZZ Ceti stars, this should be complemented with detailed asteroseismic analysis using the individual observed periods.
Palabras clave:
STARS: EVOLUTION
,
STARS: INTERIORS
,
STARS: OSCILLATIONS
,
WHITE DWARFS
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(IALP)
Articulos de INST.DE ASTROFISICA LA PLATA
Articulos de INST.DE ASTROFISICA LA PLATA
Citación
de Gerónimo, Francisco César; Abadi, Diego Alejandro; Althaus, Leandro Gabriel; Wachlin, Felipe Carlos; Camisassa, María Eugenia; Pulsation properties of ultra-massive DA white dwarf stars with ONe cores; EDP Sciences; Astronomy and Astrophysics; 621; 1-2019; 1-10
Compartir
Altmétricas