J01020100-7122208: an accreted evolved blue straggler that wasn't ejected from a supermassive black hole
| Autor: | Sergey E. Koposov, Douglas Bourbert, Paula Jofre, Danielle de Brito Silva, J. L. Prieto, Keith Hawkins |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
Supermassive black hole abundances [Galaxy] Astronomy FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics - Astrophysics of Galaxies Blue straggler abundances [stars] Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) halo [Galaxy] Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) individual: J01020100-7122208 [stars] |
| Zdroj: | de Brito-Silva, D, Jofré, P, Bourbert, D, Koposov, S E, Prieto, J L & Hawkins, K 2022, ' J01020100-7122208: an accreted evolved blue straggler that wasn't ejected from a supermassive black hole ', Monthly Notices of the Royal Astronomical Society, vol. 509, no. 3, pp. 4637-4652 . https://doi.org/10.1093/mnras/stab3364 |
| DOI: | 10.48550/arxiv.2111.08821 |
| Popis: | J01020100-7122208 is a star whose origin and nature still challenges us. It was first believed to be a yellow super giant ejected from the Small Magellanic Cloud, but it was more recently claimed to be a red giant accelerated by the Milky Way's central black hole. In order to unveil its nature, we analysed photometric, astrometric and high resolution spectroscopic observations to estimate the orbit, age, and 16 elemental abundances. Our results show that this star has a retrograde and highly-eccentric orbit, $e=0.914_{-0.020}^{+0.016}$. Correspondingly, it likely crossed the Galactic disk at $550\;\mathrm{pc}$ from the Galactic centre. We obtained a spectroscopic mass and age of $1.09\pm0.10$ $M_\odot$ and $4.51\pm1.44$ Gyr respectively. Its chemical composition is similar to the abundance of other retrograde halo stars. We found that the star is enriched in europium, having [Eu/Fe] = 0.93 $\pm$ 0.24, and is more metal-poor than reported in the literature, with [Fe/H] = -1.30 $\pm$ 0.10. This information was used to conclude that J01020100-7122208 is likely not a star ejected from the central black of the Milky Way or from the Small Magellanic Cloud. Instead, we propose that it is simply a halo star which was likely accreted by the Milky Way in the distant past but its mass and age suggest it is probably an evolved blue straggler. Comment: 17 pages, 9 Figures, accepted for publication in Monthly Notices of the Royal Astronomical Society |
| Databáze: | OpenAIRE |
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