Sakari, CM;
Roederer, IU;
Placco, VM;
Beers, TC;
Ezzeddine, R;
Frebel, A;
Hansen, T;
... Watson, F; + view all
(2019)
The R-Process Alliance: Discovery of a Low-alpha, r-process-enhanced Metal-poor Star in the Galactic Halo.
Astrophysical Journal
, 874
(2)
, Article 148. 10.3847/1538-4357/ab0c02.
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Abstract
A new moderately r-process-enhanced metal-poor star, RAVE J093730.5−062655, has been identified in the Milky Way halo as part of an ongoing survey by the R-Process Alliance. The temperature and surface gravity indicate that J0937−0626 is likely a horizontal branch star. At [Fe/H] = −1.86, J0937−0626 is found to have subsolar [X/Fe] ratios for nearly every light, α, and Fe-peak element. The low [α/Fe] ratios can be explained by an ~0.6 dex excess of Fe; J0937−0626 is therefore similar to the subclass of "iron-enhanced" metal-poor stars. A comparison with Milky Way field stars at [Fe/H] = −2.5 suggests that J0937−0626 was enriched in material from an event, possibly a Type Ia supernova, that created a significant amount of Cr, Mn, Fe, and Ni and smaller amounts of Ca, Sc, Ti, and Zn. The r-process enhancement of J0937−0626 is likely due to a separate event, which suggests that its birth environment was highly enriched in r-process elements. The kinematics of J0937−0626, based on Gaia DR2 data, indicate a retrograde orbit in the Milky Way halo; J0937−0626 was therefore likely accreted from a dwarf galaxy that had significant r-process enrichment.
| Type: | Article |
|---|---|
| Title: | The R-Process Alliance: Discovery of a Low-alpha, r-process-enhanced Metal-poor Star in the Galactic Halo |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/ab0c02 |
| Publisher version: | https://doi.org/10.3847/1538-4357/ab0c02 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Galaxy: formation – stars: abundances – stars: atmospheres – stars: fundamental parameters – stars: individua |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10072608 |
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