| Full text | |
| Author(s): |
Placco, Vinicius M.
[1, 2]
;
Frebel, Anna
[3]
;
Beers, Timothy C.
[1, 4]
;
Christlieb, Norbert
[5]
;
Lee, Young Sun
[6]
;
Kennedy, Catherine R.
[7]
;
Rossi, Silvia
[2]
;
Santucci, Rafael M.
[2]
Total Authors: 8
|
| Affiliation: | [1] Natl Opt Astron Observ, Tucson, AZ 85719 - USA
[2] Univ Sao Paulo, Dept Astron, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil
[3] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 - USA
[4] Michigan State Univ, JINA, E Lansing, MI 48824 - USA
[5] Heidelberg Univ, Zentrum Astron, D-69117 Heidelberg - Germany
[6] New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 - USA
[7] Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611 - Australia
Total Affiliations: 7
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 781, n. 1 JAN 20 2014. |
| Web of Science Citations: | 25 |
| Abstract | |
We report on the discovery of seven low-metallicity stars selected from the Hamburg/ESO Survey, six of which are extremely metal-poor (EMP, {[}Fe/H] <= -3.0), with four having {[}Fe/H] <= -3.5. Chemical abundances or upper limits are derived for these stars based on high-resolution (R similar to 35,000) Magellan/MIKE spectroscopy, and are in general agreement with those of other very and extremely metal-poor stars reported in the literature. Accurate metallicities and abundance patterns for stars in this metallicity range are of particular importance for studies of the shape of the metallicity distribution function of the Milky Way's halo system, in particular for probing the nature of its low-metallicity tail. In addition, taking into account suggested evolutionary mixing effects, we find that six of the program stars (with {[}Fe/H] <= -3.35) possess atmospheres that were likely originally enriched in carbon, relative to iron, during their main-sequence phases. These stars do not exhibit overabundances of their s-process elements, and hence may be, within the error bars, additional examples of the so-called CEMP-no class of objects. (AU) | |
| FAPESP's process: | 12/13722-1 - (Re)Discovery and analysis of metal-poor stars in the Milky Way |
| Grantee: | Vinicius Moris Placco |
| Support Opportunities: | Scholarships abroad - Research Internship - Post-doctor |