Improved synthetic spectra of helium-core white dwarf stars

We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the atmosphere, particularly an improved representation of the state of t...

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Autores principales: Rohrmann, René, Serenelli, Aldo Marcelo, Althaus, Leandro Gabriel, Benvenuto, Omar Gustavo
Formato: Articulo
Lenguaje:Inglés
Publicado: 2002
Materias:
Ciencias Astronómicas
Atomic Processes
Stars: Atmospheres
Stars: Evolution
White Dwarfs
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/93539
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-93539
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
Atomic Processes
Stars: Atmospheres
Stars: Evolution
White Dwarfs
spellingShingle Ciencias Astronómicas
Atomic Processes
Stars: Atmospheres
Stars: Evolution
White Dwarfs
Rohrmann, René
Serenelli, Aldo Marcelo
Althaus, Leandro Gabriel
Benvenuto, Omar Gustavo
Improved synthetic spectra of helium-core white dwarf stars
topic_facet Ciencias Astronómicas
Atomic Processes
Stars: Atmospheres
Stars: Evolution
White Dwarfs
description We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the atmosphere, particularly an improved representation of the state of the gas by taking into account non-ideal effects according to the so-called occupation probability formalism. The present calculations also incorporate hydrogen-line opacity from Lyman, Balmer and Paschen series, pseudo-continuum absorptions and new updated induced-dipole absorption from H2-H2, H2-He and H-He pairs. We find that the non-ideal effects and line absorption alter the appearance of the stellar spectrum and have a significant influence upon the photometric colours in the UBVRI-JHKL system. This occurs specially for hot models Teff ≳ 8000 owing to line and pseudo-continuum opacities, and for cool models Teff ≲ 4000 where the perturbation of atoms and molecules by neighbouring particles affects the chemical equilibrium of the gas. In the present study, we also include new cooling sequences for helium-core white dwarfs of very low mass (0.160 and 0.148 M⊙) with metallicity Z = 0.02. These computations provide theoretical support to search for and identify white dwarfs of very low mass, specially useful for recent and future observational studies of globular clusters, where these objects have began to be detected.
format Articulo
Articulo
author Rohrmann, René
Serenelli, Aldo Marcelo
Althaus, Leandro Gabriel
Benvenuto, Omar Gustavo
author_facet Rohrmann, René
Serenelli, Aldo Marcelo
Althaus, Leandro Gabriel
Benvenuto, Omar Gustavo
author_sort Rohrmann, René
title Improved synthetic spectra of helium-core white dwarf stars
title_short Improved synthetic spectra of helium-core white dwarf stars
title_full Improved synthetic spectra of helium-core white dwarf stars
title_fullStr Improved synthetic spectra of helium-core white dwarf stars
title_full_unstemmed Improved synthetic spectra of helium-core white dwarf stars
title_sort improved synthetic spectra of helium-core white dwarf stars
publishDate 2002
url http://sedici.unlp.edu.ar/handle/10915/93539
work_keys_str_mv AT rohrmannrene improvedsyntheticspectraofheliumcorewhitedwarfstars
AT serenellialdomarcelo improvedsyntheticspectraofheliumcorewhitedwarfstars
AT althausleandrogabriel improvedsyntheticspectraofheliumcorewhitedwarfstars
AT benvenutoomargustavo improvedsyntheticspectraofheliumcorewhitedwarfstars
bdutipo_str Repositorios
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