DQ white-dwarf stars with low C abundance: Possible progenitors
<b>Aims.</b> The present paper focuses on the evolution of hydrogen-deficient white dwarfs with the aim of exploring the consequences of different initial envelope structures on the carbon abundances expected in helium-rich, carbon-contaminated DQ white dwarfs. In particular, the evoluti...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2006 |
| País: | Argentina |
| Institución: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/83352 |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/83352 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Astronómicas Stars: abundances Stars: evolution Stars: interiors Stars: white dwarfs |
| Sumario: | <b>Aims.</b> The present paper focuses on the evolution of hydrogen-deficient white dwarfs with the aim of exploring the consequences of different initial envelope structures on the carbon abundances expected in helium-rich, carbon-contaminated DQ white dwarfs. In particular, the evolutionary link between the DQs with low detected carbon abundances and the PG 1159, extreme horizontal branch, and helium-rich R Coronae Borealis (RCrB) stars is explored. <b>Methods.</b> We present full evolutionary calculations that take a self-consistent treatment of element diffusion into account as well as expectations for the outer layer chemical stratification of progenitor stars upon entering the white dwarf regime. <b>Results.</b> We find that PG 1159 stars cannot be related to any DQ white dwarfs with low C abundances. Instead, we suggest that the latter could constitute the progeny of the giant, helium-rich RCrB stars. |
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