| Full text | |
| Author(s): Show less - |
Melendez, Jorge
[1]
;
Ramirez, Ivan
[2, 3]
;
Karakas, Amanda I.
[4]
;
Yong, David
[4]
;
Monroe, TalaWanda R.
[1]
;
Bedell, Megan
[5]
;
Bergemann, Maria
[6]
;
Asplund, Martin
[4]
;
Maia, Marcelo Tucci
[1]
;
Bean, Jacob
[5]
;
do Nascimento, Jr., Jose-Dias
[7, 8]
;
Bazot, Michael
[9]
;
Alves-Brito, Alan
[10]
;
Freitas, Fabricio C.
[1]
;
Castro, Matthieu
Total Authors: 15
|
| Affiliation: | [1] Univ Sao Paulo, Dept Astron, IAG USP, BR-05508900 Sao Paulo - Brazil
[2] Univ Texas Austin, Dept Astron, Austin, TX 78712 - USA
[3] Univ Texas Austin, McDonald Observ, Austin, TX 78712 - USA
[4] Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611 - Australia
[5] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 - USA
[6] Univ Cambridge, Inst Astron, Cambridge CB3 0HA - England
[7] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 - USA
[8] Univ Fed Rio Grande do Norte, Dept Fis Teor & Expt, BR-59072970 Natal, RN - Brazil
[9] Univ Porto, Ctr Astrofis, P-4150762 Oporto - Portugal
[10] Univ Fed Rio Grande do Sul, Inst Fis, Porto Alegre, RS - Brazil
Total Affiliations: 10
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 791, n. 1 AUG 10 2014. |
| Web of Science Citations: | 34 |
| Abstract | |
We study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high-resolution (R similar to 110,000), high signal-to-noise ratio (800-1,000) Very Large Telescope UVES spectra, which allow us to achieve a precision of about 0.005 dex in differential abundances. The effective temperature and surface gravity of 18 Sco are T-eff = 5823 +/- 6 K and log g = 4.45 +/- 0.02 dex, i.e., 18 Sco is 46 +/- 6 K hotter than the Sun and log g is 0.01 +/- 0.02 dex higher. Its metallicity is {[}Fe/H] = 0.054 +/- 0.005 dex, and its microturbulence velocity is +0.02 +/- 0.01 km s-1 higher than solar. Our precise stellar parameters and differential isochrone analysis show that 18 Sco has a mass of 1.04 +/- 0.02 M-circle dot and that it is similar to 1.6 Gyr younger than the Sun. We use precise High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities to search for planets, but none are detected. The chemical abundance pattern of 18 Sco displays a clear trend with condensation temperature, thus showing higher abundances of refractories in 18 Sco than in the Sun. Intriguingly, there are enhancements in the neutron-capture elements relative to the Sun. Despite the small element-to-element abundance differences among nearby n-capture elements (similar to 0.02 dex), we successfully reproduce the r-process pattern in the Solar System. This is independent evidence for the universality of the r process. Our results have important implications for chemical tagging in our Galaxy and nucleosynthesis in general. (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 |
| FAPESP's process: | 10/19810-4 - Probing planet formation with chemical abundances of solar type stars |
| Grantee: | TalaWanda Rose Monroe |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |