The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5
We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] ≤ –2.5, of which 86 are extremely metal poor, [Fe/H] ≤ –3.0. Our program stars include 10 new objects with [Fe/...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2013
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| Online Access: | http://hdl.handle.net/1721.1/76327 https://orcid.org/0000-0002-2139-7145 |
| _version_ | 1826189457286496256 |
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| author | Frebel, Anna L. Yong, David Bessell, M. S. Christlieb, N. Asplund, M. Beers, Timothy C. Barklem, P. S. Ryan, S. G. Norris, John E. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Frebel, Anna L. Yong, David Bessell, M. S. Christlieb, N. Asplund, M. Beers, Timothy C. Barklem, P. S. Ryan, S. G. Norris, John E. |
| author_sort | Frebel, Anna L. |
| collection | MIT |
| description | We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] ≤ –2.5, of which 86 are extremely metal poor, [Fe/H] ≤ –3.0. Our program stars include 10 new objects with [Fe/H] ≤ –3.5. We identify a sample of "normal" metal-poor stars and measure the trends between [X/Fe] and [Fe/H], as well as the dispersion about the mean trend for this sample. Using this mean trend, we identify objects that are chemically peculiar relative to "normal" stars at the same metallicity. These chemically unusual stars include CEMP-no objects, one star with high [Si/Fe], another with high [Ba/Sr], and one with unusually low [X/Fe] for all elements heavier than Na. The Sr and Ba abundances indicate that there may be two nucleosynthetic processes at lowest metallicity that are distinct from the main r-process. Finally, for many elements, we find a significant trend between [X/Fe] versus T eff, which likely reflects non-LTE and/or three-dimensional effects. Such trends demonstrate that care must be exercised when using abundance measurements in metal-poor stars to constrain chemical evolution and/or nucleosynthesis predictions. |
| first_indexed | 2024-09-23T08:14:59Z |
| format | Article |
| id | mit-1721.1/76327 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:14:59Z |
| publishDate | 2013 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/763272022-09-23T11:54:24Z The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5 Frebel, Anna L. Yong, David Bessell, M. S. Christlieb, N. Asplund, M. Beers, Timothy C. Barklem, P. S. Ryan, S. G. Norris, John E. Massachusetts Institute of Technology. Department of Physics Frebel, Anna L. We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] ≤ –2.5, of which 86 are extremely metal poor, [Fe/H] ≤ –3.0. Our program stars include 10 new objects with [Fe/H] ≤ –3.5. We identify a sample of "normal" metal-poor stars and measure the trends between [X/Fe] and [Fe/H], as well as the dispersion about the mean trend for this sample. Using this mean trend, we identify objects that are chemically peculiar relative to "normal" stars at the same metallicity. These chemically unusual stars include CEMP-no objects, one star with high [Si/Fe], another with high [Ba/Sr], and one with unusually low [X/Fe] for all elements heavier than Na. The Sr and Ba abundances indicate that there may be two nucleosynthetic processes at lowest metallicity that are distinct from the main r-process. Finally, for many elements, we find a significant trend between [X/Fe] versus T eff, which likely reflects non-LTE and/or three-dimensional effects. Such trends demonstrate that care must be exercised when using abundance measurements in metal-poor stars to constrain chemical evolution and/or nucleosynthesis predictions. 2013-01-22T18:43:53Z 2013-01-22T18:43:53Z 2012-12 2012-04 Article http://purl.org/eprint/type/JournalArticle http://hdl.handle.net/1721.1/76327 Yong, David et al. “The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5” The Astrophysical Journal 762.1 (2013): 26. https://orcid.org/0000-0002-2139-7145 en_US http://dx.doi.org/10.1088/0004-637X/762/1/26 Astrophysical Journal Creative Commons Attribution-Noncommercial-Share Alike 3.0 http://creativecommons.org/licenses/by-nc-sa/3.0/ application/pdf IOP Publishing arXiv |
| spellingShingle | Frebel, Anna L. Yong, David Bessell, M. S. Christlieb, N. Asplund, M. Beers, Timothy C. Barklem, P. S. Ryan, S. G. Norris, John E. The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5 |
| title | The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5 |
| title_full | The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5 |
| title_fullStr | The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5 |
| title_full_unstemmed | The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5 |
| title_short | The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] ≤ -3.5 |
| title_sort | most metal poor stars ii chemical abundances of 190 metal poor stars including 10 new stars with fe h ≤ 3 5 |
| url | http://hdl.handle.net/1721.1/76327 https://orcid.org/0000-0002-2139-7145 |
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