An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant
White dwarfs are dense, cooling stellar embers consisting mostly of carbon and oxygen, or oxygen and neon (with a few percent carbon) at higher initial stellar masses. These stellar cores are enveloped by a shell of helium which in turn is usually surrounded by a layer of hydrogen, generally prohibi...
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| Autores principales: | , , , , , , , , , , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
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2020
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/125123 |
| Aporte de: |
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I19-R120-10915-125123 |
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| record_format |
dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Astronómicas Astronomía White dwarfs Carbon Hydrogen |
| spellingShingle |
Ciencias Astronómicas Astronomía White dwarfs Carbon Hydrogen Hollands, Mark Tremblay, Pier-Emmanuel Gänsicke, Boris T. Camisassa, María Eugenia Koester, Detlev Aungwerojwit, A. Chote, Paul Córsico, Alejandro Hugo Dhillon, Vik S. Gentile Fusillo, N. P. Hoskin, M. J. Izquierdo, Paula Marsh, Tom Steeghs, Danny An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant |
| topic_facet |
Ciencias Astronómicas Astronomía White dwarfs Carbon Hydrogen |
| description |
White dwarfs are dense, cooling stellar embers consisting mostly of carbon and oxygen, or oxygen and neon (with a few percent carbon) at higher initial stellar masses. These stellar cores are enveloped by a shell of helium which in turn is usually surrounded by a layer of hydrogen, generally prohibiting direct observation of the interior composition. However, carbon is observed at the surface of a sizeable fraction of white dwarfs, sometimes with traces of oxygen, and it is thought to be dredged-up from the core by a deep helium convection zone. In these objects only traces of hydrogen are found as large masses of hydrogen are predicted to inhibit hydrogen/helium convective mixing within the envelope. We report the identification of WDJ055134.612+413531.09, an ultra-massive (1.14 solar masses (M⊙)) white dwarf with a unique hydrogen/carbon mixed atmosphere (C/H=0.15 in number ratio). Our analysis of the envelope and interior indicates that the total hydrogen and helium mass fractions must be several orders of magnitude lower than predictions of single star evolution: less than 10<sup>−9.5</sup> and 10<sup>−7.0</sup>, respectively. Due to the fast kinematics (129 ± 5 km s<sup>−1</sup> relative to the local standard of rest), large mass, and peculiar envelope composition, we argue that WDJ0551+4135 is consistent with formation from the merger of two white dwarfs in a tight binary system. |
| format |
Articulo Articulo |
| author |
Hollands, Mark Tremblay, Pier-Emmanuel Gänsicke, Boris T. Camisassa, María Eugenia Koester, Detlev Aungwerojwit, A. Chote, Paul Córsico, Alejandro Hugo Dhillon, Vik S. Gentile Fusillo, N. P. Hoskin, M. J. Izquierdo, Paula Marsh, Tom Steeghs, Danny |
| author_facet |
Hollands, Mark Tremblay, Pier-Emmanuel Gänsicke, Boris T. Camisassa, María Eugenia Koester, Detlev Aungwerojwit, A. Chote, Paul Córsico, Alejandro Hugo Dhillon, Vik S. Gentile Fusillo, N. P. Hoskin, M. J. Izquierdo, Paula Marsh, Tom Steeghs, Danny |
| author_sort |
Hollands, Mark |
| title |
An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant |
| title_short |
An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant |
| title_full |
An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant |
| title_fullStr |
An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant |
| title_full_unstemmed |
An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant |
| title_sort |
ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant |
| publishDate |
2020 |
| url |
http://sedici.unlp.edu.ar/handle/10915/125123 |
| work_keys_str_mv |
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Repositorios |
| _version_ |
1764820451274522624 |