An R-process enhanced star in the dwarf galaxy Tucana III
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 satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the -process and can be classified as an -I star. DES J235532 is the first -I star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain -process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with -I and -II stars found in other dwarf galaxies and in the Milky Way halo suggests a common astrophysical origin for the neutron-capture elements seen in all -process enhanced stars. We explore both internal and external scenarios for the -process enrichment of Tuc III and show that with abundance patterns for additional stars it should be possible to distinguish between them.
Keywords
Cite
@article{arxiv.1702.07430,
title = {An R-process enhanced star in the dwarf galaxy Tucana III},
author = {T. T. Hansen and J. D. Simon and J. L. Marshall and T. S. Li and D. Carollo and D. L. DePoy and D. Q. Nagasawa and R. A. Bernstein and A. Drlica-Wagner and F. B. Abdalla and S. Allam and J. Annis and K. Bechtol and A. Benoit-Lévy and D. Brooks and E. Buckley-Geer and A. Carnero Rosell and M. Carrasco Kind and J. Carretero and C. E. Cunha and L. N. da Costa and S. Desai and T. F. Eifler and A. Fausti Neto and B. Flaugher and J. Frieman and J. García-Bellido and E. Gaztanaga and D. W. Gerdes and D. Gruen and R. A. Gruendl and J. Gschwend and G. Gutierrez and D. J. James and E. Krause and K. Kuehn and N. Kuropatkin and O. Lahav and R. Miquel and A. A. Plazas and A. K. Romer and E. Sanchez and B. Santiago and V. Scarpine and R. C. Smith and M. Soares-Santos and F. Sobreira and E. Suchyta and M. E. C. Swanson and G. Tarle and A. R. Walker},
journal= {arXiv preprint arXiv:1702.07430},
year = {2017}
}
Comments
12 pages, 5 figures. Accepted for publication in ApJ