METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5
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 ~ 35,000) Magellan/M...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2014
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| Online Access: | http://hdl.handle.net/1721.1/88509 https://orcid.org/0000-0002-2139-7145 |
| _version_ | 1826197941304426496 |
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| author | Placco, Vinicius M. Beers, Timothy C. Christlieb, N. Lee, Young Sun Kennedy, Catherine R. Rossi, Silvia Santucci, Rafael M. Frebel, Anna L. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Placco, Vinicius M. Beers, Timothy C. Christlieb, N. Lee, Young Sun Kennedy, Catherine R. Rossi, Silvia Santucci, Rafael M. Frebel, Anna L. |
| author_sort | Placco, Vinicius M. |
| collection | MIT |
| description | 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 ~ 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. |
| first_indexed | 2024-09-23T10:56:08Z |
| format | Article |
| id | mit-1721.1/88509 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:56:08Z |
| publishDate | 2014 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/885092022-10-01T00:02:59Z METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5 Placco, Vinicius M. Beers, Timothy C. Christlieb, N. Lee, Young Sun Kennedy, Catherine R. Rossi, Silvia Santucci, Rafael M. Frebel, Anna L. Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Frebel, Anna L. 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 ~ 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. 2014-07-28T20:04:41Z 2014-07-28T20:04:41Z 2014-01 2013-08 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/88509 Placco, Vinicius M., Anna Frebel, Timothy C. Beers, Norbert Christlieb, Young Sun Lee, Catherine R. Kennedy, Silvia Rossi, and Rafael M. Santucci. “METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ⩽ –3.5.” The Astrophysical Journal 781, no. 1 (January 20, 2014): 40. https://orcid.org/0000-0002-2139-7145 en_US http://dx.doi.org/10.1088/0004-637X/781/1/40 The Astrophysical Journal Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf IOP Publishing arXiv |
| spellingShingle | Placco, Vinicius M. Beers, Timothy C. Christlieb, N. Lee, Young Sun Kennedy, Catherine R. Rossi, Silvia Santucci, Rafael M. Frebel, Anna L. METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5 |
| title | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5 |
| title_full | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5 |
| title_fullStr | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5 |
| title_full_unstemmed | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5 |
| title_short | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] ≤ –3.5 |
| title_sort | metal poor stars observed with the magellan telescope ii discovery of four stars with fe h ≤ 3 5 |
| url | http://hdl.handle.net/1721.1/88509 https://orcid.org/0000-0002-2139-7145 |
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