The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2
All rights reserved.. A high-resolution spectroscopic analysis is presented for a new highly r-process-enhanced ([Eu/Fe] = 1.27, [Ba/Eu] = -0.65), very metal-poor ([Fe/H] = -2.09), retrograde halo star, RAVE J153830.9-180424, discovered as part of the R-Process Alliance survey. At V = 10.86, this is...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
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American Astronomical Society
2018
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| Online Access: | http://hdl.handle.net/1721.1/118126 https://orcid.org/0000-0002-2139-7145 |
| _version_ | 1826218170782842880 |
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| author | Sakari, Charli M. Placco, Vinicius M. Hansen, Terese Holmbeck, Erika M. Beers, Timothy C. Roederer, Ian U. Venn, Kim A. Wallerstein, George Davis, Christopher Evan Farrell, Elizabeth M. Yong, David Frebel, Anna L. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Sakari, Charli M. Placco, Vinicius M. Hansen, Terese Holmbeck, Erika M. Beers, Timothy C. Roederer, Ian U. Venn, Kim A. Wallerstein, George Davis, Christopher Evan Farrell, Elizabeth M. Yong, David Frebel, Anna L. |
| author_sort | Sakari, Charli M. |
| collection | MIT |
| description | All rights reserved.. A high-resolution spectroscopic analysis is presented for a new highly r-process-enhanced ([Eu/Fe] = 1.27, [Ba/Eu] = -0.65), very metal-poor ([Fe/H] = -2.09), retrograde halo star, RAVE J153830.9-180424, discovered as part of the R-Process Alliance survey. At V = 10.86, this is the brightest and most metal-rich r-II star known in the Milky Way halo. Its brightness enables high-S/N detections of a wide variety of chemical species that are mostly created by the r-process, including some infrequently detected lines from elements like Ru, Pd, Ag, Tm, Yb, Lu, Hf, and Th, with upper limits on Pb and U. This is the most complete r-process census in a very metal-poor r-II star. J1538-1804 shows no signs of s-process contamination, based on its low [Ba/Eu] and [Pb/Fe]. As with many other r-process-enhanced stars, J1538-1804's r-process pattern matches that of the Sun for elements between the first, second, and third peaks, and does not exhibit an actinide boost. Cosmo-chronometric age-dating reveals the r-process material to be quite old. This robust main r-process pattern is a necessary constraint for r-process formation scenarios (of particular interest in light of the recent neutron star merger, GW170817), and has important consequences for the origins of r-II stars. Additional r-I and r-II stars will be reported by the R-Process Alliance in the near future. |
| first_indexed | 2024-09-23T17:15:08Z |
| format | Article |
| id | mit-1721.1/118126 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T17:15:08Z |
| publishDate | 2018 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1181262022-09-30T00:45:22Z The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2 Sakari, Charli M. Placco, Vinicius M. Hansen, Terese Holmbeck, Erika M. Beers, Timothy C. Roederer, Ian U. Venn, Kim A. Wallerstein, George Davis, Christopher Evan Farrell, Elizabeth M. Yong, David Frebel, Anna L. Massachusetts Institute of Technology. Department of Physics Frebel, Anna L. All rights reserved.. A high-resolution spectroscopic analysis is presented for a new highly r-process-enhanced ([Eu/Fe] = 1.27, [Ba/Eu] = -0.65), very metal-poor ([Fe/H] = -2.09), retrograde halo star, RAVE J153830.9-180424, discovered as part of the R-Process Alliance survey. At V = 10.86, this is the brightest and most metal-rich r-II star known in the Milky Way halo. Its brightness enables high-S/N detections of a wide variety of chemical species that are mostly created by the r-process, including some infrequently detected lines from elements like Ru, Pd, Ag, Tm, Yb, Lu, Hf, and Th, with upper limits on Pb and U. This is the most complete r-process census in a very metal-poor r-II star. J1538-1804 shows no signs of s-process contamination, based on its low [Ba/Eu] and [Pb/Fe]. As with many other r-process-enhanced stars, J1538-1804's r-process pattern matches that of the Sun for elements between the first, second, and third peaks, and does not exhibit an actinide boost. Cosmo-chronometric age-dating reveals the r-process material to be quite old. This robust main r-process pattern is a necessary constraint for r-process formation scenarios (of particular interest in light of the recent neutron star merger, GW170817), and has important consequences for the origins of r-II stars. Additional r-I and r-II stars will be reported by the R-Process Alliance in the near future. 2018-09-18T14:01:53Z 2018-09-18T14:01:53Z 2018-02 2018-01 2018-08-28T12:11:18Z Article http://purl.org/eprint/type/JournalArticle 2041-8213 http://hdl.handle.net/1721.1/118126 Sakari, Charli M., Vinicius M. Placco, Terese Hansen, Erika M. Holmbeck, Timothy C. Beers, Anna Frebel, Ian U. Roederer, et al. “The r-Process Pattern of a Bright, Highly r-Process-Enhanced Metal-Poor Halo Star at [Fe/H] ∼ −2.” The Astrophysical Journal 854, no. 2 (February 14, 2018): L20. https://orcid.org/0000-0002-2139-7145 http://dx.doi.org/10.3847/2041-8213/AAA9B4 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 American Astronomical Society IOP Publishing |
| spellingShingle | Sakari, Charli M. Placco, Vinicius M. Hansen, Terese Holmbeck, Erika M. Beers, Timothy C. Roederer, Ian U. Venn, Kim A. Wallerstein, George Davis, Christopher Evan Farrell, Elizabeth M. Yong, David Frebel, Anna L. The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2 |
| title | The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2 |
| title_full | The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2 |
| title_fullStr | The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2 |
| title_full_unstemmed | The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2 |
| title_short | The r-process Pattern of a Bright, Highly r -process-enhanced Metal-poor Halo Star at [Fe/H ] ~ -2 |
| title_sort | r process pattern of a bright highly r process enhanced metal poor halo star at fe h 2 |
| url | http://hdl.handle.net/1721.1/118126 https://orcid.org/0000-0002-2139-7145 |
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