Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates
- Autores
- Deal, M.; Deheuvels, S.; Vauclair, G.; Vauclair, S.; Wachlin, Felipe Carlos
- Año de publicación
- 2013
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- Context. Recent observations of a large number of DA and DB white dwarfs show evidence of debris disks, which are the remnants of old planetary systems. The infrared excess detected with Spitzer and the lines of heavy elements observed in their atmospheres with high-resolution spectroscopy converge on the idea that planetary material accretes onto these stars. Accretion rates have been derived by several authors with the assumption of a steady state between accretion and gravitational settling. The results are unrealistically different for DA and DB white dwarfs. Aims. When heavy matter is accreted onto stars, it induces an inverse μ-gradient that leads to fingering (thermohaline) convection. The aim of this letter is to study the impact of this specific process on the derived accretion rates in white dwarfs and on the difference between DA and DB. Methods. We solve the diffusion equation for the accreted heavy elements with a time-dependent method. The models we use have been obtained both with the IRAP code, which computes static models, and the La Plata code, which computes evolutionary sequences. Computations with pure gravitational settling are compared with computations that include fingering convection. Results. The most important result is that fingering convection has very important effects on DAs but is inefficient in DBs. When only gravitational settling is taken into account, the time-dependent computations lead to a steady state, as postulated by previous authors. When fingering convection is added, this steady state occurs much later. Conclusions. The surprising difference found in the past for the accretion rates derived for DA and DB white dwarfs disappears. The derived accretion rates for DAs are increased when fingering convection is taken into account, whereas those for DBs are not modified. More precise and developed results will be given in a forthcoming paper
Fil: Deal, M.. Université de Toulouse; Francia
Fil: Deheuvels, S.. Université de Toulouse; Francia
Fil: Vauclair, G.. Université de Toulouse; Francia
Fil: Vauclair, S.. Université de Toulouse; Francia
Fil: Wachlin, Felipe Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Astrofísica de la Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina - Materia
-
White dwarfs
Planetary systems
Accretion disks
Convection
Diffusion
Hydrodynamics - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/8524
Ver los metadatos del registro completo
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Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion ratesDeal, M.Deheuvels, S.Vauclair, G.Vauclair, S.Wachlin, Felipe CarlosWhite dwarfsPlanetary systemsAccretion disksConvectionDiffusionHydrodynamicshttps://purl.org/becyt/ford/1.7https://purl.org/becyt/ford/1https://purl.org/becyt/ford/1.7https://purl.org/becyt/ford/1Context. Recent observations of a large number of DA and DB white dwarfs show evidence of debris disks, which are the remnants of old planetary systems. The infrared excess detected with Spitzer and the lines of heavy elements observed in their atmospheres with high-resolution spectroscopy converge on the idea that planetary material accretes onto these stars. Accretion rates have been derived by several authors with the assumption of a steady state between accretion and gravitational settling. The results are unrealistically different for DA and DB white dwarfs. Aims. When heavy matter is accreted onto stars, it induces an inverse μ-gradient that leads to fingering (thermohaline) convection. The aim of this letter is to study the impact of this specific process on the derived accretion rates in white dwarfs and on the difference between DA and DB. Methods. We solve the diffusion equation for the accreted heavy elements with a time-dependent method. The models we use have been obtained both with the IRAP code, which computes static models, and the La Plata code, which computes evolutionary sequences. Computations with pure gravitational settling are compared with computations that include fingering convection. Results. The most important result is that fingering convection has very important effects on DAs but is inefficient in DBs. When only gravitational settling is taken into account, the time-dependent computations lead to a steady state, as postulated by previous authors. When fingering convection is added, this steady state occurs much later. Conclusions. The surprising difference found in the past for the accretion rates derived for DA and DB white dwarfs disappears. The derived accretion rates for DAs are increased when fingering convection is taken into account, whereas those for DBs are not modified. More precise and developed results will be given in a forthcoming paperFil: Deal, M.. Université de Toulouse; FranciaFil: Deheuvels, S.. Université de Toulouse; FranciaFil: Vauclair, G.. Université de Toulouse; FranciaFil: Vauclair, S.. Université de Toulouse; FranciaFil: Wachlin, Felipe Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Astrofísica de la Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaEdp Sciences2013-09info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/8524Deal, M.; Deheuvels, S.; Vauclair, G.; Vauclair, S.; Wachlin, Felipe Carlos; Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates; Edp Sciences; Astronomy And Astrophysics; 557; 4; 9-2013; 1-40004-6361enginfo:eu-repo/semantics/altIdentifier/url/http://www.aanda.org/articles/aa/abs/2013/09/aa22206-13/aa22206-13.htmlinfo:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201322206info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:34:24Zoai:ri.conicet.gov.ar:11336/8524instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 10:34:24.911CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates |
title |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates |
spellingShingle |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates Deal, M. White dwarfs Planetary systems Accretion disks Convection Diffusion Hydrodynamics |
title_short |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates |
title_full |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates |
title_fullStr |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates |
title_full_unstemmed |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates |
title_sort |
Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates |
dc.creator.none.fl_str_mv |
Deal, M. Deheuvels, S. Vauclair, G. Vauclair, S. Wachlin, Felipe Carlos |
author |
Deal, M. |
author_facet |
Deal, M. Deheuvels, S. Vauclair, G. Vauclair, S. Wachlin, Felipe Carlos |
author_role |
author |
author2 |
Deheuvels, S. Vauclair, G. Vauclair, S. Wachlin, Felipe Carlos |
author2_role |
author author author author |
dc.subject.none.fl_str_mv |
White dwarfs Planetary systems Accretion disks Convection Diffusion Hydrodynamics |
topic |
White dwarfs Planetary systems Accretion disks Convection Diffusion Hydrodynamics |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.7 https://purl.org/becyt/ford/1 https://purl.org/becyt/ford/1.7 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
Context. Recent observations of a large number of DA and DB white dwarfs show evidence of debris disks, which are the remnants of old planetary systems. The infrared excess detected with Spitzer and the lines of heavy elements observed in their atmospheres with high-resolution spectroscopy converge on the idea that planetary material accretes onto these stars. Accretion rates have been derived by several authors with the assumption of a steady state between accretion and gravitational settling. The results are unrealistically different for DA and DB white dwarfs. Aims. When heavy matter is accreted onto stars, it induces an inverse μ-gradient that leads to fingering (thermohaline) convection. The aim of this letter is to study the impact of this specific process on the derived accretion rates in white dwarfs and on the difference between DA and DB. Methods. We solve the diffusion equation for the accreted heavy elements with a time-dependent method. The models we use have been obtained both with the IRAP code, which computes static models, and the La Plata code, which computes evolutionary sequences. Computations with pure gravitational settling are compared with computations that include fingering convection. Results. The most important result is that fingering convection has very important effects on DAs but is inefficient in DBs. When only gravitational settling is taken into account, the time-dependent computations lead to a steady state, as postulated by previous authors. When fingering convection is added, this steady state occurs much later. Conclusions. The surprising difference found in the past for the accretion rates derived for DA and DB white dwarfs disappears. The derived accretion rates for DAs are increased when fingering convection is taken into account, whereas those for DBs are not modified. More precise and developed results will be given in a forthcoming paper Fil: Deal, M.. Université de Toulouse; Francia Fil: Deheuvels, S.. Université de Toulouse; Francia Fil: Vauclair, G.. Université de Toulouse; Francia Fil: Vauclair, S.. Université de Toulouse; Francia Fil: Wachlin, Felipe Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Astrofísica de la Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina |
description |
Context. Recent observations of a large number of DA and DB white dwarfs show evidence of debris disks, which are the remnants of old planetary systems. The infrared excess detected with Spitzer and the lines of heavy elements observed in their atmospheres with high-resolution spectroscopy converge on the idea that planetary material accretes onto these stars. Accretion rates have been derived by several authors with the assumption of a steady state between accretion and gravitational settling. The results are unrealistically different for DA and DB white dwarfs. Aims. When heavy matter is accreted onto stars, it induces an inverse μ-gradient that leads to fingering (thermohaline) convection. The aim of this letter is to study the impact of this specific process on the derived accretion rates in white dwarfs and on the difference between DA and DB. Methods. We solve the diffusion equation for the accreted heavy elements with a time-dependent method. The models we use have been obtained both with the IRAP code, which computes static models, and the La Plata code, which computes evolutionary sequences. Computations with pure gravitational settling are compared with computations that include fingering convection. Results. The most important result is that fingering convection has very important effects on DAs but is inefficient in DBs. When only gravitational settling is taken into account, the time-dependent computations lead to a steady state, as postulated by previous authors. When fingering convection is added, this steady state occurs much later. Conclusions. The surprising difference found in the past for the accretion rates derived for DA and DB white dwarfs disappears. The derived accretion rates for DAs are increased when fingering convection is taken into account, whereas those for DBs are not modified. More precise and developed results will be given in a forthcoming paper |
publishDate |
2013 |
dc.date.none.fl_str_mv |
2013-09 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://hdl.handle.net/11336/8524 Deal, M.; Deheuvels, S.; Vauclair, G.; Vauclair, S.; Wachlin, Felipe Carlos; Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates; Edp Sciences; Astronomy And Astrophysics; 557; 4; 9-2013; 1-4 0004-6361 |
url |
http://hdl.handle.net/11336/8524 |
identifier_str_mv |
Deal, M.; Deheuvels, S.; Vauclair, G.; Vauclair, S.; Wachlin, Felipe Carlos; Accretion from debris disks onto white dwarfs. Fingering (thermohaline) instability and derived accretion rates; Edp Sciences; Astronomy And Astrophysics; 557; 4; 9-2013; 1-4 0004-6361 |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/http://www.aanda.org/articles/aa/abs/2013/09/aa22206-13/aa22206-13.html info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201322206 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
dc.format.none.fl_str_mv |
application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
Edp Sciences |
publisher.none.fl_str_mv |
Edp Sciences |
dc.source.none.fl_str_mv |
reponame:CONICET Digital (CONICET) instname:Consejo Nacional de Investigaciones Científicas y Técnicas |
reponame_str |
CONICET Digital (CONICET) |
collection |
CONICET Digital (CONICET) |
instname_str |
Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.name.fl_str_mv |
CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.mail.fl_str_mv |
dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar |
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1844614361075679232 |
score |
13.070432 |