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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.)

High precision differential abundance measurements in globular clusters: chemical inhomogeneities in NGC 6752

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Autor(es):
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Yong, David [1] ; Melendez, Jorge [2] ; Grundahl, Frank [3] ; Roederer, Ian U. [4] ; Norris, John E. [1] ; Milone, A. P. [1] ; Marino, A. F. [1] ; Coelho, P. [5] ; McArthur, Barbara E. [6] ; Lind, K. [7] ; Collet, R. [1] ; Asplund, Martin [1]
Número total de Autores: 12
Afiliação do(s) autor(es):
[1] Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611 - Australia
[2] Univ Sao Paulo, Dept Astron IAG, BR-05508900 Sao Paulo - Brazil
[3] Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, DK-8000 Aarhus C - Denmark
[4] Carnegie Observ, Pasadena, CA 91101 - USA
[5] Univ Cruzeiro Sul, Nucleo Astrofis Teor, BR-01506000 Sao Paulo - Brazil
[6] Univ Texas Austin, McDonald Observ, Austin, TX 78712 - USA
[7] Univ Cambridge, Cambridge CB3 0HA - England
Número total de Afiliações: 7
Tipo de documento: Artigo Científico
Fonte: Monthly Notices of the Royal Astronomical Society; v. 434, n. 4, p. 3542-3565, OCT 2013.
Citações Web of Science: 46
Resumo

We report on a strictly differential line-by-line analysis of high-quality UVES spectra of bright giants in the metal-poor globular cluster NGC 6752. We achieved high precision differential chemical abundance measurements for Fe, Na, Si, Ca, Ti, Cr, Ni, Zn, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy with uncertainties as low as similar to 0.01 dex (similar to 2 per cent). We obtained the following main results. (1) The observed abundance dispersions are a factor of similar to 2 larger than the average measurement uncertainty. (2) There are positive correlations, of high statistical significance, between all elements and Na. (3) For any pair of elements, there are positive correlations of high statistical significance, although the amplitudes of the abundance variations are small. Removing abundance trends with effective temperature and/or using a different pair of reference stars does not alter these results. These abundance variations and correlations may reflect a combination of (a) He abundance variations and (b) inhomogeneous chemical evolution in the pre- or protocluster environment. Regarding the former, the current constraints on delta Y from photometry likely preclude He as being the sole explanation. Regarding the latter, the nucleosynthetic source(s) must have synthesized Na, alpha, Fe-peak and neutron-capture elements and in constant amounts for species heavier than Si; no individual object can achieve such nucleosynthesis. We speculate that other, if not all, globular clusters may exhibit comparable abundance variations and correlations to NGC 6752 if subjected to a similarly precise analysis. (AU)

Processo FAPESP: 10/17510-3 - Influência da formação de planetas na composição química de estrelas do tipo solar
Beneficiário:Jorge Luis Melendez Moreno
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 12/24392-2 - Espectroscopia de alta precisão: impacto no estudo de planetas, estrelas, a galáxia e cosmologia
Beneficiário:Jorge Luis Melendez Moreno
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 08/58406-4 - A modelagem de populações estelares e padrões de abundância detalhados
Beneficiário:Paula Rodrigues Teixeira Coelho
Linha de fomento: Auxílio à Pesquisa - Apoio a Jovens Pesquisadores