The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Outros Autores: | , , , , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/201488 |
Resumo: | Context. The nature of the recently identified “sdA” spectroscopic class of stars is not well understood. The thousands of known sdAs have H-dominated spectra, spectroscopic surface gravity values between main sequence stars and isolated white dwarfs, and effective temperatures below the lower limit for He-burning subdwarfs. Most are likely products of binary stellar evolution, whether extremely low-mass white dwarfs and their precursors or blue stragglers in the halo. Aims. Stellar eigenfrequencies revealed through time series photometry of pulsating stars sensitively probe stellar structural properties. The properties of pulsations exhibited by sdA stars would contribute substantially to our developing understanding of this class. Methods. We extend our photometric campaign to discover pulsating extremely low-mass white dwarfs from the McDonald Observatory to target sdA stars classified from SDSS spectra. We also obtain follow-up time series spectroscopy to search for binary signatures from four new pulsators. Results. Out of 23 sdA stars observed, we clearly detect stellar pulsations in 7. Dominant pulsation periods range from 4.6 min to 12.3 h, with most on timescales of approximately one hour. We argue specific classifications for some of the new variables, identifying both compact and likely main sequence dwarf pulsators, along with a candidate low-mass RR Lyrae star. Conclusions. With dominant pulsation periods spanning orders of magnitude, the pulsational evidence supports the emerging narrative that the sdA class consists of multiple stellar populations. Since multiple types of sdA exhibit stellar pulsations, follow-up asteroseismic analysis can be used to probe the precise evolutionary natures and stellar structures of these individual subpopulations. |
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Bell, KeatonPelisoli, Ingrid DomingosKepler, Souza OliveiraBrown, Warren R.Winget, Donald EarlWinget, K. I.Vanderbosch, ZacharyCastanheira, Bárbara GarciaHermes, James J.Montgomery, Michael HoustonKoester, Detlev2019-11-09T03:50:47Z20180004-6361http://hdl.handle.net/10183/201488001104447Context. The nature of the recently identified “sdA” spectroscopic class of stars is not well understood. The thousands of known sdAs have H-dominated spectra, spectroscopic surface gravity values between main sequence stars and isolated white dwarfs, and effective temperatures below the lower limit for He-burning subdwarfs. Most are likely products of binary stellar evolution, whether extremely low-mass white dwarfs and their precursors or blue stragglers in the halo. Aims. Stellar eigenfrequencies revealed through time series photometry of pulsating stars sensitively probe stellar structural properties. The properties of pulsations exhibited by sdA stars would contribute substantially to our developing understanding of this class. Methods. We extend our photometric campaign to discover pulsating extremely low-mass white dwarfs from the McDonald Observatory to target sdA stars classified from SDSS spectra. We also obtain follow-up time series spectroscopy to search for binary signatures from four new pulsators. Results. Out of 23 sdA stars observed, we clearly detect stellar pulsations in 7. Dominant pulsation periods range from 4.6 min to 12.3 h, with most on timescales of approximately one hour. We argue specific classifications for some of the new variables, identifying both compact and likely main sequence dwarf pulsators, along with a candidate low-mass RR Lyrae star. Conclusions. With dominant pulsation periods spanning orders of magnitude, the pulsational evidence supports the emerging narrative that the sdA class consists of multiple stellar populations. Since multiple types of sdA exhibit stellar pulsations, follow-up asteroseismic analysis can be used to probe the precise evolutionary natures and stellar structures of these individual subpopulations.application/pdfengAstronomy and astrophysics. Les Ulis. Vol. 617 (Sep. 2018), A6, 11 p.Anãs brancasEvolucao estelarPulsacoes estelaresStars: oscillationsStars: variables: generalSubdwarfsWhite dwarfsGalaxy: stellar contentThe McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populationsEstrangeiroinfo: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:UFRGSTEXT001104447.pdf.txt001104447.pdf.txtExtracted Texttext/plain62492http://www.lume.ufrgs.br/bitstream/10183/201488/2/001104447.pdf.txta7a78fa44a9909b54c8109087dc20233MD52ORIGINAL001104447.pdfTexto completo (inglês)application/pdf792841http://www.lume.ufrgs.br/bitstream/10183/201488/1/001104447.pdf1e1597fd672a4348512e009429a8c727MD5110183/2014882021-05-07 04:46:58.20808oai:www.lume.ufrgs.br:10183/201488Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2021-05-07T07:46:58Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations |
title |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations |
spellingShingle |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations Bell, Keaton Anãs brancas Evolucao estelar Pulsacoes estelares Stars: oscillations Stars: variables: general Subdwarfs White dwarfs Galaxy: stellar content |
title_short |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations |
title_full |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations |
title_fullStr |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations |
title_full_unstemmed |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations |
title_sort |
The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations |
author |
Bell, Keaton |
author_facet |
Bell, Keaton Pelisoli, Ingrid Domingos Kepler, Souza Oliveira Brown, Warren R. Winget, Donald Earl Winget, K. I. Vanderbosch, Zachary Castanheira, Bárbara Garcia Hermes, James J. Montgomery, Michael Houston Koester, Detlev |
author_role |
author |
author2 |
Pelisoli, Ingrid Domingos Kepler, Souza Oliveira Brown, Warren R. Winget, Donald Earl Winget, K. I. Vanderbosch, Zachary Castanheira, Bárbara Garcia Hermes, James J. Montgomery, Michael Houston Koester, Detlev |
author2_role |
author author author author author author author author author author |
dc.contributor.author.fl_str_mv |
Bell, Keaton Pelisoli, Ingrid Domingos Kepler, Souza Oliveira Brown, Warren R. Winget, Donald Earl Winget, K. I. Vanderbosch, Zachary Castanheira, Bárbara Garcia Hermes, James J. Montgomery, Michael Houston Koester, Detlev |
dc.subject.por.fl_str_mv |
Anãs brancas Evolucao estelar Pulsacoes estelares |
topic |
Anãs brancas Evolucao estelar Pulsacoes estelares Stars: oscillations Stars: variables: general Subdwarfs White dwarfs Galaxy: stellar content |
dc.subject.eng.fl_str_mv |
Stars: oscillations Stars: variables: general Subdwarfs White dwarfs Galaxy: stellar content |
description |
Context. The nature of the recently identified “sdA” spectroscopic class of stars is not well understood. The thousands of known sdAs have H-dominated spectra, spectroscopic surface gravity values between main sequence stars and isolated white dwarfs, and effective temperatures below the lower limit for He-burning subdwarfs. Most are likely products of binary stellar evolution, whether extremely low-mass white dwarfs and their precursors or blue stragglers in the halo. Aims. Stellar eigenfrequencies revealed through time series photometry of pulsating stars sensitively probe stellar structural properties. The properties of pulsations exhibited by sdA stars would contribute substantially to our developing understanding of this class. Methods. We extend our photometric campaign to discover pulsating extremely low-mass white dwarfs from the McDonald Observatory to target sdA stars classified from SDSS spectra. We also obtain follow-up time series spectroscopy to search for binary signatures from four new pulsators. Results. Out of 23 sdA stars observed, we clearly detect stellar pulsations in 7. Dominant pulsation periods range from 4.6 min to 12.3 h, with most on timescales of approximately one hour. We argue specific classifications for some of the new variables, identifying both compact and likely main sequence dwarf pulsators, along with a candidate low-mass RR Lyrae star. Conclusions. With dominant pulsation periods spanning orders of magnitude, the pulsational evidence supports the emerging narrative that the sdA class consists of multiple stellar populations. Since multiple types of sdA exhibit stellar pulsations, follow-up asteroseismic analysis can be used to probe the precise evolutionary natures and stellar structures of these individual subpopulations. |
publishDate |
2018 |
dc.date.issued.fl_str_mv |
2018 |
dc.date.accessioned.fl_str_mv |
2019-11-09T03:50:47Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
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info:eu-repo/semantics/publishedVersion |
format |
article |
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publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/201488 |
dc.identifier.issn.pt_BR.fl_str_mv |
0004-6361 |
dc.identifier.nrb.pt_BR.fl_str_mv |
001104447 |
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0004-6361 001104447 |
url |
http://hdl.handle.net/10183/201488 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Astronomy and astrophysics. Les Ulis. Vol. 617 (Sep. 2018), A6, 11 p. |
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info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
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application/pdf |
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