Discovery of an ultramassive pulsating white dwarf
dc.contributor.author | Hermes, James J. | pt_BR |
dc.contributor.author | Kepler, Souza Oliveira | pt_BR |
dc.contributor.author | Castanheira, Bárbara Garcia | pt_BR |
dc.contributor.author | Gianninas, Alexandros | pt_BR |
dc.contributor.author | Winget, Donald Earl | pt_BR |
dc.contributor.author | Montgomery, Michael Houston | pt_BR |
dc.contributor.author | Brown, Warren R. | pt_BR |
dc.contributor.author | Harrold, Samuel T. | pt_BR |
dc.date.accessioned | 2015-01-20T02:15:19Z | pt_BR |
dc.date.issued | 2013 | pt_BR |
dc.identifier.issn | 0004-637X | pt_BR |
dc.identifier.uri | http://hdl.handle.net/10183/109061 | pt_BR |
dc.description.abstract | We announce the discovery of themostmassive pulsating hydrogen-atmosphere white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12,030 ± 210 K WD with a log g = 9.08 ± 0.06, which corresponds to a mass of 1.20 ± 0.03M . Stellar evolution models indicate that the progenitor of such a high-mass WD endured a stable carbon-burning phase, producing an oxygen–neon-core WD. The discovery of pulsations in GD 518 thus offers the first opportunity to probe the interior of a WD with a possible oxygen–neon core. Such amassiveWDshould also be significantly crystallized at this temperature. The star exhibits multi-periodic luminosity variations at timescales ranging from roughly 425 to 595 s and amplitudes up to 0.7%, consistent in period and amplitude with the observed variability of typical ZZ Ceti stars, which exhibit non-radial g-mode pulsations driven by a hydrogen partial ionization zone. Successfully unraveling both the total mass and core composition of GD 518 provides a unique opportunity to investigate intermediate-mass stellar evolution, and can possibly place an upper limit to the mass of a carbon–oxygen-core WD, which in turn constrains Type Ia supernovae progenitor systems. | en |
dc.format.mimetype | application/pdf | |
dc.language.iso | eng | pt_BR |
dc.relation.ispartof | The astrophysical journal. Bristol. Vol. 771, no. 1 (July 2013), L2, 5 p. | pt_BR |
dc.rights | Open Access | en |
dc.subject | Stars: evolution | en |
dc.subject | Evolucao estelar | pt_BR |
dc.subject | Pulsacoes estelares | pt_BR |
dc.subject | Stars: individual (GD 518) | en |
dc.subject | Stars: oscillations | en |
dc.subject | Espectros estelares | pt_BR |
dc.subject | Anãs brancas | pt_BR |
dc.subject | Stars: variables: general | en |
dc.subject | Supernovae: general | en |
dc.subject | White dwarfs | en |
dc.title | Discovery of an ultramassive pulsating white dwarf | pt_BR |
dc.type | Artigo de periódico | pt_BR |
dc.identifier.nrb | 000918022 | pt_BR |
dc.type.origin | Estrangeiro | pt_BR |
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