METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS
We report the discovery of one extremely metal-poor (EMP; [Fe/H] < -3) and one ultra metal-poor (UMP; [Fe/H] < -4) star selected from the Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding and Exploration survey. These stars were identified as EMP candidates based on their med...
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/100039 https://orcid.org/0000-0001-7727-1640 https://orcid.org/0000-0002-2139-7145 |
| _version_ | 1826210992576528384 |
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| author | Placco, Vinicius M. Lee, Young Sun Beers, Timothy C. Pena, Jose M. Chan, Conrad Heger, Alexander Frebel, Anna L. Jacobson, Heather |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Placco, Vinicius M. Lee, Young Sun Beers, Timothy C. Pena, Jose M. Chan, Conrad Heger, Alexander Frebel, Anna L. Jacobson, Heather |
| author_sort | Placco, Vinicius M. |
| collection | MIT |
| description | We report the discovery of one extremely metal-poor (EMP; [Fe/H] < -3) and one ultra metal-poor (UMP; [Fe/H] < -4) star selected from the Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding and Exploration survey. These stars were identified as EMP candidates based on their medium-resolution (R ~ 2000) spectra, and were followed up with high-resolution (R ~ 35,000) spectroscopy with the Magellan/Clay Telescope. Their derived chemical abundances exhibit good agreement with those of stars with similar metallicities. We also provide new insights on the formation of the UMP stars, based on comparisons with a new set of theoretical models of supernovae (SNe) nucleosynthesis. The models were matched with 20 UMP stars found in the literature, together with one of the program stars (SDSS J1204+1201), with [Fe/H] = -4.34. From fitting their abundances, we find that the SNe progenitors, for stars where carbon and nitrogen are measured, had masses ranging from 20.5 M[subscript ʘ] to 28 M[subscript ʘ] and explosion energies from 0.3 to 0.9 X 10[superscript 51] erg. These results are highly sensitive to the carbon and nitrogen abundance determinations, which is one of the main drivers for a future high-resolution follow-up of UMP candidates. In addition, we are able to reproduce the different CNO abundance patterns found in UMP stars with a single progenitor type by varying its mass and explosion energy. |
| first_indexed | 2024-09-23T14:58:41Z |
| format | Article |
| id | mit-1721.1/100039 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T14:58:41Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1000392022-09-29T11:52:03Z METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS Placco, Vinicius M. Lee, Young Sun Beers, Timothy C. Pena, Jose M. Chan, Conrad Heger, Alexander Frebel, Anna L. Jacobson, Heather Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Frebel, Anna L. Jacobson, Heather R. Pena, Jose M. We report the discovery of one extremely metal-poor (EMP; [Fe/H] < -3) and one ultra metal-poor (UMP; [Fe/H] < -4) star selected from the Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding and Exploration survey. These stars were identified as EMP candidates based on their medium-resolution (R ~ 2000) spectra, and were followed up with high-resolution (R ~ 35,000) spectroscopy with the Magellan/Clay Telescope. Their derived chemical abundances exhibit good agreement with those of stars with similar metallicities. We also provide new insights on the formation of the UMP stars, based on comparisons with a new set of theoretical models of supernovae (SNe) nucleosynthesis. The models were matched with 20 UMP stars found in the literature, together with one of the program stars (SDSS J1204+1201), with [Fe/H] = -4.34. From fitting their abundances, we find that the SNe progenitors, for stars where carbon and nitrogen are measured, had masses ranging from 20.5 M[subscript ʘ] to 28 M[subscript ʘ] and explosion energies from 0.3 to 0.9 X 10[superscript 51] erg. These results are highly sensitive to the carbon and nitrogen abundance determinations, which is one of the main drivers for a future high-resolution follow-up of UMP candidates. In addition, we are able to reproduce the different CNO abundance patterns found in UMP stars with a single progenitor type by varying its mass and explosion energy. National Science Foundation (U.S.) (CAREER Grant AST-1255160) 2015-11-24T19:10:28Z 2015-11-24T19:10:28Z 2015-08 2015-06 Article http://purl.org/eprint/type/JournalArticle 1538-4357 0004-637X http://hdl.handle.net/1721.1/100039 Placco, Vinicius M., Anna Frebel, Young Sun Lee, Heather R. Jacobson, Timothy C. Beers, Jose M. Pena, Conrad Chan, and Alexander Heger. “METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS.” The Astrophysical Journal 809, no. 2 (August 19, 2015): 136. © 2015 The American Astronomical Society https://orcid.org/0000-0001-7727-1640 https://orcid.org/0000-0002-2139-7145 en_US http://dx.doi.org/10.1088/0004-637x/809/2/136 The Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing IOP Publishing |
| spellingShingle | Placco, Vinicius M. Lee, Young Sun Beers, Timothy C. Pena, Jose M. Chan, Conrad Heger, Alexander Frebel, Anna L. Jacobson, Heather METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS |
| title | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS |
| title_full | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS |
| title_fullStr | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS |
| title_full_unstemmed | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS |
| title_short | METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. III. NEW EXTREMELY AND ULTRA METAL-POOR STARS FROM SDSS/SEGUE AND INSIGHTS ON THE FORMATION OF ULTRA METAL-POOR STARS |
| title_sort | metal poor stars observed with the magellan telescope iii new extremely and ultra metal poor stars from sdss segue and insights on the formation of ultra metal poor stars |
| url | http://hdl.handle.net/1721.1/100039 https://orcid.org/0000-0001-7727-1640 https://orcid.org/0000-0002-2139-7145 |
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