| Full text | |
| Author(s): |
Tucci Maia, M.
[1]
;
Ramirez, I.
[2, 3]
;
Melendez, J.
[1]
;
Bedell, M.
[4]
;
Bean, J. L.
[4]
;
Asplund, M.
[5]
Total Authors: 6
|
| Affiliation: | [1] Univ Sao Paulo, Dept Astron IAG USP, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil
[2] Univ Texas Austin, McDonald Observ, Austin, TX 78712 - USA
[3] Univ Texas Austin, Dept Astron Austin, Austin, TX 78712 - USA
[4] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 - USA
[5] Australian Natl Univ, Res Sch Astron & Astrophys, Cotter Rd, Weston, ACT 2611 - Australia
Total Affiliations: 5
|
| Document type: | Journal article |
| Source: | Astronomy & Astrophysics; v. 590, JUN 2016. |
| Web of Science Citations: | 29 |
| Abstract | |
Context. Solar twins are stars with similar stellar (surface) parameters to the Sun that can have a wide range of ages. This provides an opportunity to analyze the variation of their chemical abundances with age. Nissen (2015, A\&A, 579, A52) recently suggested that the abundances of the s-process element Y and the alpha-element Mg could be used to estimate stellar ages. Aims. This paper aims to determine with high precision the Y, Mg, and Fe abundances for a sample of 88 solar twins that span a broad age range (0.3-10.0 Gyr) and investigate their use for estimating ages. Methods. We obtained high-quality Magellan Inamori Kyocera Echelle (MIKE) spectra and determined Y and Mg abundances using equivalent widths and a line-by-line differential method within a 1D LTE framework. Stellar parameters and iron abundances were measured in Paper I of this series for all stars, but a few (three) required a small revision. Results. The {[}Y/Mg] ratio shows a strong correlation with age. It has a slope of 0 : 041 +/- 0 : 001 dex/Gyr and a significance of 41 sigma. This is in excellent agreement with the relation first proposed by Nissen (2015). We found some outliers that turned out to be binaries where mass transfer may have enhanced the yttrium abundance. Given a precise measurement of {[}Y/Mg] with typical error of 0.02 dex in solar twins, our formula can be used to determine a stellar age with similar to 0.8 Gyr precision in the 0 to 10 Gyr range. (AU) | |
| FAPESP's process: | 12/24392-2 - High precision spectroscopy: impact in the study of planets, stars, the galaxy and cosmology |
| Grantee: | Jorge Luis Melendez Moreno |
| Support Opportunities: | Research Projects - Thematic Grants |