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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.)

ELEMENTAL ABUNDANCE DIFFERENCES IN THE 16 CYGNI BINARY SYSTEM: A SIGNATURE OF GAS GIANT PLANET FORMATION?

Texto completo
Autor(es):
Ramirez, I. [1] ; Melendez, J. [2] ; Cornejo, D. [3] ; Roederer, I. U. [1] ; Fish, J. R. [1, 4]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Observ Carnegie Inst Sci, Pasadena, CA 91101 - USA
[2] Univ Sao Paulo, Dept Astron IAG USP, BR-05508900 Sao Paulo - Brazil
[3] Agencia Espacial Peru CONIDA, Dept Astrofis, Lima - Peru
[4] Harvey Mudd Coll, Claremont, CA 91711 - USA
Número total de Afiliações: 4
Tipo de documento: Artigo Científico
Fonte: ASTROPHYSICAL JOURNAL; v. 740, n. 2 OCT 20 2011.
Citações Web of Science: 62
Resumo

The atmospheric parameters of the components of the 16 Cygni binary system, in which the secondary has a gas giant planet detected, are measured accurately using high-quality observational data. Abundances relative to solar are obtained for 25 elements with a mean error of sigma({[}X/H]) = 0.023 dex. The fact that 16 Cyg A has about four times more lithium than 16 Cyg B is normal considering the slightly different masses of the stars. The abundance patterns of 16 Cyg A and B, relative to iron, are typical of that observed inmost of the so-called solar twin stars, with the exception of the heavy elements (Z > 30), which can, however, be explained by Galactic chemical evolution. Differential (A-B) abundances are measured with even higher precision (sigma(Delta{[}X/H]) = 0.018 dex, on average). We find that 16 Cyg A is more metal-rich than 16 Cyg B by Delta{[}M/H] = +0.041 +/- 0.007 dex. On an element-to-element basis, no correlation between the A-B abundance differences and dust condensation temperature (T(C)) is detected. Based on these results, we conclude that if the process of planet formation around 16 Cyg B is responsible for the observed abundance pattern, the formation of gas giants produces a constant downward shift in the photospheric abundance of metals, without a T(C) correlation. The latter would be produced by the formation of terrestrial planets instead, as suggested by other recent works on precise elemental abundances. Nevertheless, a scenario consistent with these observations requires the convective envelopes of similar or equal to 1 M(circle dot) stars to reach their present-day sizes about three times quicker than predicted by standard stellar evolution models. (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