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An r-process Enhanced Star in the Dwarf Galaxy Tucana III

Hansen, TT; Simon, JD; Marshall, JL; Li, TS; Carollo, D; DePoy, DL; Nagasawa, DQ; ... Walker, AR; + view all (2017) An r-process Enhanced Star in the Dwarf Galaxy Tucana III. Astrophysical Journal , 838 (1) 10.3847/1538-4357/aa634a. Green open access

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Abstract

Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate Tucana III. Because it is particularly bright for a star in an ultra-faint Milky Way (MW) satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66−593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the r-process and can be classified as an r-I star. DES J235532 is the first r-I star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain r-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with r-I and r-II stars found in other dwarf galaxies and in the MW halo suggests a common astrophysical origin for the neutron-capture elements seen in all r-process enhanced stars. We explore both internal and external scenarios for the r-process enrichment of Tuc III and show that with abundance patterns for additional stars, it should be possible to distinguish between them.

Type: Article
Title: An r-process Enhanced Star in the Dwarf Galaxy Tucana III
Open access status: An open access version is available from UCL Discovery
DOI: 10.3847/1538-4357/aa634a
Publisher version: http://dx.doi.org/10.3847/1538-4357/aa634a
Language: English
Additional information: © 2017. The American Astronomical Society. All rights reserved
Keywords: Science & Technology, Physical Sciences, Astronomy & Astrophysics, Galaxies: Abundances, Galaxies: Dwarf, Stars: Abundances, Stars: Chemically Peculiar, Metal-Poor Stars, Horizontal-Branch Stars, Dark Energy Survey, Red Giant Branch, Spheroidal Galaxy, Chemical Evolution, Process Nucleosynthesis, Spectroscopic Analysis, Detailed Abundances, Globular-Clusters
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 Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/1556158
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