An r-process enhanced star in the dwarf galaxy Tucana III*

Romer, A K and The DES Collaboration, (2017) An r-process enhanced star in the dwarf galaxy Tucana III*. Astrophysical Journal, 838 (1). a44. ISSN 0004-637X

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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.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QB Astronomy
Depositing User: Billy Wichaidit
Date Deposited: 10 May 2017 11:09
Last Modified: 11 May 2017 00:24
URI: http://sro.sussex.ac.uk/id/eprint/68037

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Project NameSussex Project NumberFunderFunder Ref
Astronomy Centre Rolling GrantG0679STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/F002858/1