The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild
We present detailed chemical abundances of three new bright (V ∼ 11), extremely metal-poor ([Fe/H] ∼-3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25 neutron-capture elements in each of our stars. J1432-4125 is among...
| Main Authors: | , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
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American Astronomical Society
2020
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| Online Access: | https://hdl.handle.net/1721.1/124741 |
| _version_ | 1826195492950769664 |
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| author | Cain, Madelyn Frebel, Anna Gull, Maude Ji, Alexander P. Placco, Vinicius M. Beers, Timothy C. Meléndez, Jorge Ezzeddine, Rana Casey, Andrew R. Hansen, Terese T. Roederer, Ian U. Sakari, Charli |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Cain, Madelyn Frebel, Anna Gull, Maude Ji, Alexander P. Placco, Vinicius M. Beers, Timothy C. Meléndez, Jorge Ezzeddine, Rana Casey, Andrew R. Hansen, Terese T. Roederer, Ian U. Sakari, Charli |
| author_sort | Cain, Madelyn |
| collection | MIT |
| description | We present detailed chemical abundances of three new bright (V ∼ 11), extremely metal-poor ([Fe/H] ∼-3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25 neutron-capture elements in each of our stars. J1432-4125 is among the most r-process-rich r-II stars, with [Eu/Fe] = +1.44 ± 0.11. J2005-3057 is an r-I star with [Eu/Fe] = +0.94 ± 0.07. J0858-0809 has [Eu/Fe] = +0.23 ± 0.05 and exhibits a carbon abundance corrected for an evolutionary status of [C/Fe]corr = +0.76, thus adding to the small number of known carbon-enhanced r-process stars. All three stars show remarkable agreement with the scaled solar r-process pattern for elements above Ba, consistent with enrichment of the birth gas cloud by a neutron star merger. The abundances for Sr, Y, and Zr, however, deviate from the scaled solar pattern. This indicates that more than one distinct r-process site might be responsible for the observed neutron-capture element abundance pattern. Thorium was detected in J1432-4125 and J2005-3057. Age estimates for J1432-4125 and J2005-3057 were adopted from one of two sets of initial production ratios each by assuming the stars are old. This yielded individual ages of 12 ± 6 Gyr and 10 ± 6 Gyr, respectively. ©2018 |
| first_indexed | 2024-09-23T10:13:32Z |
| format | Article |
| id | mit-1721.1/124741 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T10:13:32Z |
| publishDate | 2020 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1247412022-09-26T16:36:00Z The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild Cain, Madelyn Frebel, Anna Gull, Maude Ji, Alexander P. Placco, Vinicius M. Beers, Timothy C. Meléndez, Jorge Ezzeddine, Rana Casey, Andrew R. Hansen, Terese T. Roederer, Ian U. Sakari, Charli Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research We present detailed chemical abundances of three new bright (V ∼ 11), extremely metal-poor ([Fe/H] ∼-3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25 neutron-capture elements in each of our stars. J1432-4125 is among the most r-process-rich r-II stars, with [Eu/Fe] = +1.44 ± 0.11. J2005-3057 is an r-I star with [Eu/Fe] = +0.94 ± 0.07. J0858-0809 has [Eu/Fe] = +0.23 ± 0.05 and exhibits a carbon abundance corrected for an evolutionary status of [C/Fe]corr = +0.76, thus adding to the small number of known carbon-enhanced r-process stars. All three stars show remarkable agreement with the scaled solar r-process pattern for elements above Ba, consistent with enrichment of the birth gas cloud by a neutron star merger. The abundances for Sr, Y, and Zr, however, deviate from the scaled solar pattern. This indicates that more than one distinct r-process site might be responsible for the observed neutron-capture element abundance pattern. Thorium was detected in J1432-4125 and J2005-3057. Age estimates for J1432-4125 and J2005-3057 were adopted from one of two sets of initial production ratios each by assuming the stars are old. This yielded individual ages of 12 ± 6 Gyr and 10 ± 6 Gyr, respectively. ©2018 NSF CAREER (grant no. AST-1255160) NSF (grant no. PHY-1430152) 2020-04-17T20:16:39Z 2020-04-17T20:16:39Z 2018-09 2018-05 2019-03-22T15:48:36Z Article http://purl.org/eprint/type/JournalArticle 1538-4357 https://hdl.handle.net/1721.1/124741 Cain, Madelyn, et al., "The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild." Astrophysical journal 864, 1 (September 2018): no. 43 doi 10.3847/1538-4357/AAD37D ©2018 Author(s) 10.3847/1538-4357/AAD37D 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 The Astrophysical Journal |
| spellingShingle | Cain, Madelyn Frebel, Anna Gull, Maude Ji, Alexander P. Placco, Vinicius M. Beers, Timothy C. Meléndez, Jorge Ezzeddine, Rana Casey, Andrew R. Hansen, Terese T. Roederer, Ian U. Sakari, Charli The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild |
| title | The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild |
| title_full | The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild |
| title_fullStr | The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild |
| title_full_unstemmed | The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild |
| title_short | The R-Process Alliance: chemical abundances for a trio of R-process-enhanced stars -- one strong, one moderate, and one mild |
| title_sort | r process alliance chemical abundances for a trio of r process enhanced stars one strong one moderate and one mild |
| url | https://hdl.handle.net/1721.1/124741 |
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