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

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...

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Detalhes bibliográficos
Autores: Hansen, Terese T., Simon, Josh D., Marshall, Jennifer L., Li, T. S., Carollo, Daniela, DePoy, Darren L., Nagasawa, Daniel Q., Bernstein, Rebecca A., Drlica-Wagner, Alex, Abdalla, Filipe B., Allam, Sahar S., Annis, James T., Bechtol, Keith, Benoit-Lévy, Aurélien, Brooks, D., Buckley-Geer, Elizabeth, Carnero Rosell, Aurelio, Carrasco Kind, Matías, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, Costa, Luiz N. da, Desai, S., Eifler, Tim, Fausti Neto, Angelo, Flaugher, Brenna, Frieman, Joshua A., García-Bellido, Juan, Gaztañaga, Enrique, Gerdes, David W., Gruen, Daniel, Gruendl, Robert A., Gschwend, Julia de Figueiredo, Gutierrez, Gaston R., James, David J., Krause, Elisabeth, Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, Miquel, Ramon, Plazas Malagón, Andrés Alejandro, Romer, Anita K., Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Scarpine, Victor Emanuel, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Walker, Alistair, DES Collaboration
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2017
País:Brasil
Recursos:Universidade Federal do Rio Grande do Sul (UFRGS)
Repositorio:Repositório Institucional da UFRGS
Idioma:inglés
OAI Identifier:oai:www.lume.ufrgs.br:10183/165644
Acesso em linha:http://hdl.handle.net/10183/165644
Access Level:acceso abierto
Palavra-chave:Captura radioativa de nêutrons
Metalicidade
Composicao estelar
Nucleosíntese
galaxies: abundances
Galaxies: dwarf
Stars: abundances
Stars: chemically peculiar
Readable tables
Supporting material: machine
Descrição
Resumo: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 rprocess 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.

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