The Hyades open cluster is chemically inhomogeneous

Autor(es)

Liu, F. ^[1] ; Yong, D. ^[1] ; Asplund, M. ^[1] ; Ramirez, I. ^{[2, 3]} ; Melendez, J. ^[4]

Afiliação do(s) autor(es)

^[1] Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611 - Australia

^[2] Univ Texas Austin, McDonald Observ, 2515 Speedway, Austin, TX 78712 - USA

^[3] Univ Texas Austin, Dept Astron, 2515 Speedway, Austin, TX 78712 - USA

^[4] Univ Sao Paulo, Dept Astron IAG USP, Rua Matao 1226, BR-05508900 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 457, n. 4, p. 3934-3948, APR 21 2016.
• Citações Web of Science: 36

Resumo

We present a high-precision differential abundance analysis of 16 solar-type stars in the Hyades open cluster based on high-resolution, high signal-to-noise ratio (S/N approximate to 350-400) spectra obtained from the McDonald 2.7-m telescope. We derived stellar parameters and differential chemical abundances for 19 elements (C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ba) with uncertainties as low as similar to 0.01-0.02 dex. Our main results include: (1) there is no clear chemical signature of planet formation detected among the sample stars, i.e. no correlations in abundances versus condensation temperature; (2) the observed abundance dispersions are a factor of approximate to 1.5-2 larger than the average measurement errors for most elements; (3) there are positive correlations, of high statistical significance, between the abundances of at least 90 per cent of pairs of elements. We demonstrate that none of these findings can be explained by errors due to the stellar parameters. Our results reveal that the Hyades is chemically inhomogeneous at the 0.02 dex level. Possible explanations for the abundance variations include (1) inhomogeneous chemical evolution in the proto-cluster environment, (2) supernova ejection in the proto-cluster cloud and (3) pollution of metal-poor gas before complete mixing of the proto-cluster cloud. Our results provide significant new constraints on the chemical composition of open clusters and a challenge to the current view of Galactic archaeology. (AU)

• Processo FAPESP: 12/24392-2 - Espectroscopia de alta precisão: impacto no estudo de planetas, estrelas, a galáxia e cosmologia
• Beneficiário: Jorge Luis Melendez Moreno
• Modalidade de apoio: Auxílio à Pesquisa - Temático