Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541
Autor(a) principal: | |
---|---|
Data de Publicação: | 2021 |
Outros Autores: | , , , , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/239515 |
Resumo: | Context. The Transiting Exoplanet Survey Satellite (TESS) mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus continuing the impulse of its predecessor, the Kepler mission. Aims. In this paper, we present the observations from the extended TESS mission in both 120 s short-cadence and 20 s ultra-short cadence mode of two pre-white dwarf stars showing hydrogen deficiency. We identify them as two new GW Vir stars, TIC 333432673 and TIC 095332541. We apply the tools of asteroseismology with the aim of deriving their structural parameters and seismological distances. Methods. We carried out a spectroscopic analysis and a spectral fitting of TIC 333432673 and TIC 095332541. We also processed and analyzed the high-precision TESS photometric light curves of the two target stars, and derived their oscillation frequencies. We performed an asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We searched for patterns of uniform period spacings in order to constrain the stellar mass of the stars. We employed the individual observed periods to search for a representative seismological model. Results. The analysis of the TESS light curves of TIC 333432673 and TIC 095332541 reveals the presence of several oscillations with periods ranging from 350 to 500 s associated to typical gravity (g)-modes. From follow-up ground-based spectroscopy, we find that both stars have a similar effective temperature (Teff = 120 000 ± 10 000 K) and surface gravity (log g = 7.5 ± 0.5), but a different He/C composition of their atmosphere. On the basis of PG 1159 evolutionary tracks, we derived a spectroscopic mass of M? = 0.58+0.16 −0.08 M for both stars. Our asteroseismological analysis of TIC 333432673 allowed us to find a constant period spacing compatible with a stellar mass M? ∼ 0.60 − 0.61 M , and an asteroseismological model for this star with a stellar mass M? = 0.589 ± 0.020 M , as well as a seismological distance of d = 459+188 −156 pc. For this star, we find an excellent agreement between the different methods to infer the stellar mass, and also between the seismological distance and that measured with Gaia (dGaia = 389+5.6 −5.2 pc). For TIC 095332541, we have found a possible period spacing that suggests a stellar mass of M? ∼ 0.55−0.57 M . Unfortunately, we have not been able to find an asteroseismological model for this star. Conclusions. Using the high-quality data collected by the TESS space mission and follow-up spectroscopy, we have been able to discover and characterize two new GW Vir stars. The TESS mission is having, and will continue to have, an unprecedented impact on the area of white-dwarf asteroseismology. |
id |
UFRGS-2_16a5a2d535ae471d004978c7a62a4237 |
---|---|
oai_identifier_str |
oai:www.lume.ufrgs.br:10183/239515 |
network_acronym_str |
UFRGS-2 |
network_name_str |
Repositório Institucional da UFRGS |
repository_id_str |
|
spelling |
Uzundag, MuratCórsico, Alejandro HugoKepler, Souza OliveiraAlthaus, Leandro GabrielWerner, KlausReindl, NicoleBell, KeatonHiggins, MichaelRosa, Gabriela Oliveira daVuckovic, MajaIstrate, Alina G.2022-05-31T01:01:21Z20210004-6361http://hdl.handle.net/10183/239515001140013Context. The Transiting Exoplanet Survey Satellite (TESS) mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus continuing the impulse of its predecessor, the Kepler mission. Aims. In this paper, we present the observations from the extended TESS mission in both 120 s short-cadence and 20 s ultra-short cadence mode of two pre-white dwarf stars showing hydrogen deficiency. We identify them as two new GW Vir stars, TIC 333432673 and TIC 095332541. We apply the tools of asteroseismology with the aim of deriving their structural parameters and seismological distances. Methods. We carried out a spectroscopic analysis and a spectral fitting of TIC 333432673 and TIC 095332541. We also processed and analyzed the high-precision TESS photometric light curves of the two target stars, and derived their oscillation frequencies. We performed an asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We searched for patterns of uniform period spacings in order to constrain the stellar mass of the stars. We employed the individual observed periods to search for a representative seismological model. Results. The analysis of the TESS light curves of TIC 333432673 and TIC 095332541 reveals the presence of several oscillations with periods ranging from 350 to 500 s associated to typical gravity (g)-modes. From follow-up ground-based spectroscopy, we find that both stars have a similar effective temperature (Teff = 120 000 ± 10 000 K) and surface gravity (log g = 7.5 ± 0.5), but a different He/C composition of their atmosphere. On the basis of PG 1159 evolutionary tracks, we derived a spectroscopic mass of M? = 0.58+0.16 −0.08 M for both stars. Our asteroseismological analysis of TIC 333432673 allowed us to find a constant period spacing compatible with a stellar mass M? ∼ 0.60 − 0.61 M , and an asteroseismological model for this star with a stellar mass M? = 0.589 ± 0.020 M , as well as a seismological distance of d = 459+188 −156 pc. For this star, we find an excellent agreement between the different methods to infer the stellar mass, and also between the seismological distance and that measured with Gaia (dGaia = 389+5.6 −5.2 pc). For TIC 095332541, we have found a possible period spacing that suggests a stellar mass of M? ∼ 0.55−0.57 M . Unfortunately, we have not been able to find an asteroseismological model for this star. Conclusions. Using the high-quality data collected by the TESS space mission and follow-up spectroscopy, we have been able to discover and characterize two new GW Vir stars. The TESS mission is having, and will continue to have, an unprecedented impact on the area of white-dwarf asteroseismology.application/pdfengAstronomy and astrophysics. Les Ulis. Vol. 655 (Nov. 2021), A27, 12 p.Evolucao estelarAnãs brancasPulsacoes estelaresAsterosismologiaAsteroseismologyStars : OscillationsStars : InteriorsStars : EvolutionWhite dwarfsPulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541Estrangeiroinfo: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:UFRGSTEXT001140013.pdf.txt001140013.pdf.txtExtracted Texttext/plain64094http://www.lume.ufrgs.br/bitstream/10183/239515/2/001140013.pdf.txtd82ab80a495ba0625b36585dfd77f2beMD52ORIGINAL001140013.pdfTexto completo (inglês)application/pdf5986169http://www.lume.ufrgs.br/bitstream/10183/239515/1/001140013.pdfd262e6b5bc00462153201a0e88e53479MD5110183/2395152022-06-03 04:35:44.508128oai:www.lume.ufrgs.br:10183/239515Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2022-06-03T07:35:44Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 |
title |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 |
spellingShingle |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 Uzundag, Murat Evolucao estelar Anãs brancas Pulsacoes estelares Asterosismologia Asteroseismology Stars : Oscillations Stars : Interiors Stars : Evolution White dwarfs |
title_short |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 |
title_full |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 |
title_fullStr |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 |
title_full_unstemmed |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 |
title_sort |
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541 |
author |
Uzundag, Murat |
author_facet |
Uzundag, Murat Córsico, Alejandro Hugo Kepler, Souza Oliveira Althaus, Leandro Gabriel Werner, Klaus Reindl, Nicole Bell, Keaton Higgins, Michael Rosa, Gabriela Oliveira da Vuckovic, Maja Istrate, Alina G. |
author_role |
author |
author2 |
Córsico, Alejandro Hugo Kepler, Souza Oliveira Althaus, Leandro Gabriel Werner, Klaus Reindl, Nicole Bell, Keaton Higgins, Michael Rosa, Gabriela Oliveira da Vuckovic, Maja Istrate, Alina G. |
author2_role |
author author author author author author author author author author |
dc.contributor.author.fl_str_mv |
Uzundag, Murat Córsico, Alejandro Hugo Kepler, Souza Oliveira Althaus, Leandro Gabriel Werner, Klaus Reindl, Nicole Bell, Keaton Higgins, Michael Rosa, Gabriela Oliveira da Vuckovic, Maja Istrate, Alina G. |
dc.subject.por.fl_str_mv |
Evolucao estelar Anãs brancas Pulsacoes estelares Asterosismologia |
topic |
Evolucao estelar Anãs brancas Pulsacoes estelares Asterosismologia Asteroseismology Stars : Oscillations Stars : Interiors Stars : Evolution White dwarfs |
dc.subject.eng.fl_str_mv |
Asteroseismology Stars : Oscillations Stars : Interiors Stars : Evolution White dwarfs |
description |
Context. The Transiting Exoplanet Survey Satellite (TESS) mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus continuing the impulse of its predecessor, the Kepler mission. Aims. In this paper, we present the observations from the extended TESS mission in both 120 s short-cadence and 20 s ultra-short cadence mode of two pre-white dwarf stars showing hydrogen deficiency. We identify them as two new GW Vir stars, TIC 333432673 and TIC 095332541. We apply the tools of asteroseismology with the aim of deriving their structural parameters and seismological distances. Methods. We carried out a spectroscopic analysis and a spectral fitting of TIC 333432673 and TIC 095332541. We also processed and analyzed the high-precision TESS photometric light curves of the two target stars, and derived their oscillation frequencies. We performed an asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We searched for patterns of uniform period spacings in order to constrain the stellar mass of the stars. We employed the individual observed periods to search for a representative seismological model. Results. The analysis of the TESS light curves of TIC 333432673 and TIC 095332541 reveals the presence of several oscillations with periods ranging from 350 to 500 s associated to typical gravity (g)-modes. From follow-up ground-based spectroscopy, we find that both stars have a similar effective temperature (Teff = 120 000 ± 10 000 K) and surface gravity (log g = 7.5 ± 0.5), but a different He/C composition of their atmosphere. On the basis of PG 1159 evolutionary tracks, we derived a spectroscopic mass of M? = 0.58+0.16 −0.08 M for both stars. Our asteroseismological analysis of TIC 333432673 allowed us to find a constant period spacing compatible with a stellar mass M? ∼ 0.60 − 0.61 M , and an asteroseismological model for this star with a stellar mass M? = 0.589 ± 0.020 M , as well as a seismological distance of d = 459+188 −156 pc. For this star, we find an excellent agreement between the different methods to infer the stellar mass, and also between the seismological distance and that measured with Gaia (dGaia = 389+5.6 −5.2 pc). For TIC 095332541, we have found a possible period spacing that suggests a stellar mass of M? ∼ 0.55−0.57 M . Unfortunately, we have not been able to find an asteroseismological model for this star. Conclusions. Using the high-quality data collected by the TESS space mission and follow-up spectroscopy, we have been able to discover and characterize two new GW Vir stars. The TESS mission is having, and will continue to have, an unprecedented impact on the area of white-dwarf asteroseismology. |
publishDate |
2021 |
dc.date.issued.fl_str_mv |
2021 |
dc.date.accessioned.fl_str_mv |
2022-05-31T01:01:21Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/239515 |
dc.identifier.issn.pt_BR.fl_str_mv |
0004-6361 |
dc.identifier.nrb.pt_BR.fl_str_mv |
001140013 |
identifier_str_mv |
0004-6361 001140013 |
url |
http://hdl.handle.net/10183/239515 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Astronomy and astrophysics. Les Ulis. Vol. 655 (Nov. 2021), A27, 12 p. |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da UFRGS instname:Universidade Federal do Rio Grande do Sul (UFRGS) instacron:UFRGS |
instname_str |
Universidade Federal do Rio Grande do Sul (UFRGS) |
instacron_str |
UFRGS |
institution |
UFRGS |
reponame_str |
Repositório Institucional da UFRGS |
collection |
Repositório Institucional da UFRGS |
bitstream.url.fl_str_mv |
http://www.lume.ufrgs.br/bitstream/10183/239515/2/001140013.pdf.txt http://www.lume.ufrgs.br/bitstream/10183/239515/1/001140013.pdf |
bitstream.checksum.fl_str_mv |
d82ab80a495ba0625b36585dfd77f2be d262e6b5bc00462153201a0e88e53479 |
bitstream.checksumAlgorithm.fl_str_mv |
MD5 MD5 |
repository.name.fl_str_mv |
Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS) |
repository.mail.fl_str_mv |
|
_version_ |
1801225057680228352 |