Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion

Motivated by the strong discrepancy between the main-sequence turnoff age and the white dwarf cooling age in the metal-rich open cluster NGC 6791, we compute a grid of white dwarf evolutionary sequences that incorporates for the first time the energy released by the processes of <SUP>22</SU...

Descripción completa

Detalles Bibliográficos
Autores principales: Althaus, Leandro Gabriel, García Berro, E., Renedo, I., Isern, J., Córsico, Alejandro Hugo, Rohrmann, René
Formato: Articulo
Lenguaje:Inglés
Publicado: 2010
Materias:
Ciencias Astronómicas
Dense matter
Diffusion
Stars: Abundances
Stars: Evolution
Stars: Interiors
White dwarfs
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/82514
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-82514
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
Dense matter
Diffusion
Stars: Abundances
Stars: Evolution
Stars: Interiors
White dwarfs
spellingShingle Ciencias Astronómicas
Dense matter
Diffusion
Stars: Abundances
Stars: Evolution
Stars: Interiors
White dwarfs
Althaus, Leandro Gabriel
García Berro, E.
Renedo, I.
Isern, J.
Córsico, Alejandro Hugo
Rohrmann, René
Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
topic_facet Ciencias Astronómicas
Dense matter
Diffusion
Stars: Abundances
Stars: Evolution
Stars: Interiors
White dwarfs
description Motivated by the strong discrepancy between the main-sequence turnoff age and the white dwarf cooling age in the metal-rich open cluster NGC 6791, we compute a grid of white dwarf evolutionary sequences that incorporates for the first time the energy released by the processes of <SUP>22</SUP>Ne sedimentation and of carbon/oxygen phase separation upon crystallization. The grid covers the mass range from 0.52 to 1.0M⊙, and is appropriate for the study of white dwarfs in metal-rich clusters. The evolutionary calculations are based on a detailed and self-consistent treatment of the energy released from these two processes, as well as on the employment of realistic carbon/oxygen profiles, of relevance for an accurate evaluation of the energy released by carbon/oxygen phase separation. We find that <SUP>22</SUP>Ne sedimentation strongly delays the cooling rate of white dwarfs stemming from progenitors with high metallicities at moderate luminosities, while carbon/oxygen phase separation adds considerable delays at lowluminosities. Cooling times are sensitive to possible uncertainties in the actual value of the diffusion coefficient of <SUP>22</SUP>Ne. Changing the diffusion coefficient by a factor of 2 leads to maximum age differences of ≈8%-20% depending on the stellar mass. We find that the magnitude of the delays resulting from chemical changes in the core is consistent with the slowdown in the white dwarf cooling rate that is required to solve the age discrepancy in NGC 6791.
format Articulo
Articulo
author Althaus, Leandro Gabriel
García Berro, E.
Renedo, I.
Isern, J.
Córsico, Alejandro Hugo
Rohrmann, René
author_facet Althaus, Leandro Gabriel
García Berro, E.
Renedo, I.
Isern, J.
Córsico, Alejandro Hugo
Rohrmann, René
author_sort Althaus, Leandro Gabriel
title Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_short Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_full Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_fullStr Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_full_unstemmed Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_sort evolution of white dwarf stars with high-metallicity progenitors: the role of 22ne diffusion
publishDate 2010
url http://sedici.unlp.edu.ar/handle/10915/82514
work_keys_str_mv AT althausleandrogabriel evolutionofwhitedwarfstarswithhighmetallicityprogenitorstheroleof22nediffusion
AT garciaberroe evolutionofwhitedwarfstarswithhighmetallicityprogenitorstheroleof22nediffusion
AT renedoi evolutionofwhitedwarfstarswithhighmetallicityprogenitorstheroleof22nediffusion
AT isernj evolutionofwhitedwarfstarswithhighmetallicityprogenitorstheroleof22nediffusion
AT corsicoalejandrohugo evolutionofwhitedwarfstarswithhighmetallicityprogenitorstheroleof22nediffusion
AT rohrmannrene evolutionofwhitedwarfstarswithhighmetallicityprogenitorstheroleof22nediffusion
bdutipo_str Repositorios
_version_ 1764820488358461442

Ejemplares similares