The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/195979 |
Resumo: | The physical nature of the sdA stars – cool hydrogen-rich objects with spectroscopic surface gravities intermediate between main-sequence and canonical-mass white dwarfs – has been elusive since they were found in Sloan Digital Sky Survey Data Release 12 spectra. The population is likely dominated by metal-poor A/F stars in the halo with overestimated surface gravities, with a small contribution of extremely low-mass white dwarfs and their precursors, i.e. ELMs and pre-ELMs. In this work, we seek to identify (pre-)ELMs with radii smaller than what is possible for main-sequence stars, allowing even for very low metallicity. We analyse 3891 sdAs previously identified in the Sloan Digital Sky Survey using Gaia DR2 data. Our Monte Carlo analysis supports that 90 of these are inconsistent with the main sequence. 37 lie close to or within the canonical white dwarf cooling sequence, while the remaining 53 lie between the canonical white dwarfs and main sequence, which we interpret as likely (pre-)ELMs given their spectral class. Of these, 30 pass more conservative criteria that allow for higher systematic uncertainties on the parallax, as well as an approximate treatment of extinction. Our identifications increase the number of known (pre-)ELMs by up to 50 per cent, demonstrating how Gaia astrometry can reveal members of the compact (pre-)ELM subpopulation of the sdA spectral class. |
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Pelisoli, Ingrid DomingosBell, KeatonKepler, Souza OliveiraKoester, Detlev2019-06-20T02:35:24Z20190035-8711http://hdl.handle.net/10183/195979001095536The physical nature of the sdA stars – cool hydrogen-rich objects with spectroscopic surface gravities intermediate between main-sequence and canonical-mass white dwarfs – has been elusive since they were found in Sloan Digital Sky Survey Data Release 12 spectra. The population is likely dominated by metal-poor A/F stars in the halo with overestimated surface gravities, with a small contribution of extremely low-mass white dwarfs and their precursors, i.e. ELMs and pre-ELMs. In this work, we seek to identify (pre-)ELMs with radii smaller than what is possible for main-sequence stars, allowing even for very low metallicity. We analyse 3891 sdAs previously identified in the Sloan Digital Sky Survey using Gaia DR2 data. Our Monte Carlo analysis supports that 90 of these are inconsistent with the main sequence. 37 lie close to or within the canonical white dwarf cooling sequence, while the remaining 53 lie between the canonical white dwarfs and main sequence, which we interpret as likely (pre-)ELMs given their spectral class. Of these, 30 pass more conservative criteria that allow for higher systematic uncertainties on the parallax, as well as an approximate treatment of extinction. Our identifications increase the number of known (pre-)ELMs by up to 50 per cent, demonstrating how Gaia astrometry can reveal members of the compact (pre-)ELM subpopulation of the sdA spectral class.application/pdfengMonthly notices of the royal astronomical society. Oxford. Vol. 482, no. 3 (Jan. 2019), p. 3831-3842Anãs brancasEvolucao estelarEstrelas binariasBinaries: generalStars: evolutionSubdwarfsWhite dwarfsThe sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometryEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT001095536.pdf.txt001095536.pdf.txtExtracted Texttext/plain65106http://www.lume.ufrgs.br/bitstream/10183/195979/2/001095536.pdf.txt09e1c762cf96e9b65b97cd8c12a40253MD52ORIGINAL001095536.pdfTexto completo (inglês)application/pdf3537263http://www.lume.ufrgs.br/bitstream/10183/195979/1/001095536.pdf81ceb3ba857f77167ed50451baec0e53MD5110183/1959792019-12-12 04:59:37.656371oai:www.lume.ufrgs.br:10183/195979Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2019-12-12T06:59:37Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry |
title |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry |
spellingShingle |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry Pelisoli, Ingrid Domingos Anãs brancas Evolucao estelar Estrelas binarias Binaries: general Stars: evolution Subdwarfs White dwarfs |
title_short |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry |
title_full |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry |
title_fullStr |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry |
title_full_unstemmed |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry |
title_sort |
The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry |
author |
Pelisoli, Ingrid Domingos |
author_facet |
Pelisoli, Ingrid Domingos Bell, Keaton Kepler, Souza Oliveira Koester, Detlev |
author_role |
author |
author2 |
Bell, Keaton Kepler, Souza Oliveira Koester, Detlev |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Pelisoli, Ingrid Domingos Bell, Keaton Kepler, Souza Oliveira Koester, Detlev |
dc.subject.por.fl_str_mv |
Anãs brancas Evolucao estelar Estrelas binarias |
topic |
Anãs brancas Evolucao estelar Estrelas binarias Binaries: general Stars: evolution Subdwarfs White dwarfs |
dc.subject.eng.fl_str_mv |
Binaries: general Stars: evolution Subdwarfs White dwarfs |
description |
The physical nature of the sdA stars – cool hydrogen-rich objects with spectroscopic surface gravities intermediate between main-sequence and canonical-mass white dwarfs – has been elusive since they were found in Sloan Digital Sky Survey Data Release 12 spectra. The population is likely dominated by metal-poor A/F stars in the halo with overestimated surface gravities, with a small contribution of extremely low-mass white dwarfs and their precursors, i.e. ELMs and pre-ELMs. In this work, we seek to identify (pre-)ELMs with radii smaller than what is possible for main-sequence stars, allowing even for very low metallicity. We analyse 3891 sdAs previously identified in the Sloan Digital Sky Survey using Gaia DR2 data. Our Monte Carlo analysis supports that 90 of these are inconsistent with the main sequence. 37 lie close to or within the canonical white dwarf cooling sequence, while the remaining 53 lie between the canonical white dwarfs and main sequence, which we interpret as likely (pre-)ELMs given their spectral class. Of these, 30 pass more conservative criteria that allow for higher systematic uncertainties on the parallax, as well as an approximate treatment of extinction. Our identifications increase the number of known (pre-)ELMs by up to 50 per cent, demonstrating how Gaia astrometry can reveal members of the compact (pre-)ELM subpopulation of the sdA spectral class. |
publishDate |
2019 |
dc.date.accessioned.fl_str_mv |
2019-06-20T02:35:24Z |
dc.date.issued.fl_str_mv |
2019 |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
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0035-8711 |
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001095536 |
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http://hdl.handle.net/10183/195979 |
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eng |
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dc.relation.ispartof.pt_BR.fl_str_mv |
Monthly notices of the royal astronomical society. Oxford. Vol. 482, no. 3 (Jan. 2019), p. 3831-3842 |
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info:eu-repo/semantics/openAccess |
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openAccess |
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