White dwarf pollution by hydrated planetary remnants: Hydrogen and Metals in WD J204713.76-125908.9
| Autor: | Roberto Raddi, Matthew J. Hoskin, Jay Farihi, Boris T. Gänsicke, Anna F. Pala, Nicola Pietro Gentile Fusillo, Andrew Swan, Christopher J. Manser, Detlev Koester, Odette Toloza, Mark Hollands, M. T. Belmonte |
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| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament de Física |
| Rok vydání: | 2020 |
| Předmět: |
Solar System
Astronomy FOS: Physical sciences Astrophysics 01 natural sciences 7. Clean energy Parent body symbols.namesake Chondrite 0103 physical sciences 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Physics Earth and Planetary Astrophysics (astro-ph.EP) Física [Àrees temàtiques de la UPC] 010308 nuclear & particles physics Balmer series White dwarf White dwarfs Astronomy and Astrophysics Planetary system Stars Accretion (astrophysics) Estels Planetary systems Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science Asteroid abundances [Stars] symbols Astronomia individual: WDJ204713.76-125908.94 [Stars] Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| DOI: | 10.48550/arxiv.2009.05053 |
| Popis: | WD J204713.76-125908.9 is a new addition to the small class of white dwarfs with helium-dominated photospheres that exhibit strong Balmer absorption lines and atmospheric metal pollution. The exceptional abundances of hydrogen observed in these stars may be the result of accretion of water-rich rocky bodies. We obtained far-ultraviolet and optical spectroscopy of WD J204713.76-125908.9 using the Cosmic Origin Spectrograph on-board the Hubble Space Telescope and X-shooter on the Very Large Telescope, and identify photospheric absorption lines of nine metals: C, O, Mg, Si, P, S, Ca, Fe and Ni. The abundance ratios are consistent with the steady state accretion of exo-planetesimal debris rich in the volatile elements carbon and oxygen, and the transitional element sulphur, by factors of seventeen, two, and four respectively compared to bulk Earth. The parent body has a composition akin to Solar System carbonaceous chondrites, and the inferred minimum mass, $1.6 \times 10^{20}$ g, is comparable to an asteroid 23 km in radius. We model the composition of the disrupted parent body, finding from our simulations a median water mass fraction of eight per cent. Comment: 14 pages, 5 figures Accepted for publication in Monthly Notices of the Royal Astronomical Society |
| Databáze: | OpenAIRE |
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