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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] <=-3.5

Texto completo
Autor(es):
Placco, Vinicius M. [1, 2] ; Frebel, Anna [3] ; Beers, Timothy C. [1, 4] ; Christlieb, Norbert [5] ; Lee, Young Sun [6] ; Kennedy, Catherine R. [7] ; Rossi, Silvia [2] ; Santucci, Rafael M. [2]
Número total de Autores: 8
Afiliação do(s) autor(es):
[1] Natl Opt Astron Observ, Tucson, AZ 85719 - USA
[2] Univ Sao Paulo, Dept Astron, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil
[3] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 - USA
[4] Michigan State Univ, JINA, E Lansing, MI 48824 - USA
[5] Heidelberg Univ, Zentrum Astron, D-69117 Heidelberg - Germany
[6] New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 - USA
[7] Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611 - Australia
Número total de Afiliações: 7
Tipo de documento: Artigo Científico
Fonte: ASTROPHYSICAL JOURNAL; v. 781, n. 1 JAN 20 2014.
Citações Web of Science: 25
Resumo

We report on the discovery of seven low-metallicity stars selected from the Hamburg/ESO Survey, six of which are extremely metal-poor (EMP, {[}Fe/H] <= -3.0), with four having {[}Fe/H] <= -3.5. Chemical abundances or upper limits are derived for these stars based on high-resolution (R similar to 35,000) Magellan/MIKE spectroscopy, and are in general agreement with those of other very and extremely metal-poor stars reported in the literature. Accurate metallicities and abundance patterns for stars in this metallicity range are of particular importance for studies of the shape of the metallicity distribution function of the Milky Way's halo system, in particular for probing the nature of its low-metallicity tail. In addition, taking into account suggested evolutionary mixing effects, we find that six of the program stars (with {[}Fe/H] <= -3.35) possess atmospheres that were likely originally enriched in carbon, relative to iron, during their main-sequence phases. These stars do not exhibit overabundances of their s-process elements, and hence may be, within the error bars, additional examples of the so-called CEMP-no class of objects. (AU)

Processo FAPESP: 12/13722-1 - (Re)Descoberta e análise de estrelas pobres em metais na Via Láctea
Beneficiário:Vinicius Moris Placco
Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado