The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known
We report the discovery of a new actinide-boost star, 2MASS J09544277+5246414, originally identified as a very bright (V = 10.1), extremely metal-poor ([Fe/H] = -2.99) K giant in the LAMOST survey, and found to be highly r-process-enhanced (r-II; [Eu/Fe] = +1.28]), during the snapshot phase of the R...
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American Astronomical Society
2020
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| Online Access: | https://hdl.handle.net/1721.1/124736 |
| _version_ | 1826200203868241920 |
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| author | Frebel, Anna |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Frebel, Anna |
| author_sort | Frebel, Anna |
| collection | MIT |
| description | We report the discovery of a new actinide-boost star, 2MASS J09544277+5246414, originally identified as a very bright (V = 10.1), extremely metal-poor ([Fe/H] = -2.99) K giant in the LAMOST survey, and found to be highly r-process-enhanced (r-II; [Eu/Fe] = +1.28]), during the snapshot phase of the R-Process Alliance (RPA). Based on a high signal-to-noise ratio (S/N), high-resolution spectrum obtained with the Harlan J. Smith 2.7 m telescope, this star is the first confirmed actinide-boost star found by RPA efforts. With an enhancement of [Th/Eu] = +0.37, 2MASS J09544277+5246414 is also the most actinide-enhanced r-II star yet discovered, and only the sixth metal-poor star with a measured uranium abundance ([U/Fe] = +1.40). Using the Th/U chronometer, we estimate an age of 13.0 ± 4.7 Gyr for this star. The unambiguous actinide-boost signature of this extremely metal-poor star, combined with additional r-process-enhanced and actinide-boost stars identified by the RPA, will provide strong constraints on the nature and origin of the r-process at early times. ©2018 |
| first_indexed | 2024-09-23T11:32:45Z |
| format | Article |
| id | mit-1721.1/124736 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T11:32:45Z |
| publishDate | 2020 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1247362022-09-27T20:14:28Z The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known Frebel, Anna Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research We report the discovery of a new actinide-boost star, 2MASS J09544277+5246414, originally identified as a very bright (V = 10.1), extremely metal-poor ([Fe/H] = -2.99) K giant in the LAMOST survey, and found to be highly r-process-enhanced (r-II; [Eu/Fe] = +1.28]), during the snapshot phase of the R-Process Alliance (RPA). Based on a high signal-to-noise ratio (S/N), high-resolution spectrum obtained with the Harlan J. Smith 2.7 m telescope, this star is the first confirmed actinide-boost star found by RPA efforts. With an enhancement of [Th/Eu] = +0.37, 2MASS J09544277+5246414 is also the most actinide-enhanced r-II star yet discovered, and only the sixth metal-poor star with a measured uranium abundance ([U/Fe] = +1.40). Using the Th/U chronometer, we estimate an age of 13.0 ± 4.7 Gyr for this star. The unambiguous actinide-boost signature of this extremely metal-poor star, combined with additional r-process-enhanced and actinide-boost stars identified by the RPA, will provide strong constraints on the nature and origin of the r-process at early times. ©2018 2020-04-17T19:15:58Z 2020-04-17T19:15:58Z 2018-06 2018-04 2019-03-22T15:41:40Z Article http://purl.org/eprint/type/JournalArticle 2041-8213 2041-8205 https://hdl.handle.net/1721.1/124736 Holmbeck, Erika M., et al., "The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known." Astrophysical journal. Letters 859, 2 (June 2018): letter 24 doi 10.3847/2041-8213/AAC722 ©2018 Author(s) 10.3847/2041-8213/AAC722 Astrophysical journal. Letters 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 Letters |
| spellingShingle | Frebel, Anna The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known |
| title | The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known |
| title_full | The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known |
| title_fullStr | The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known |
| title_full_unstemmed | The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known |
| title_short | The R-Process Alliance: 2MASS J09544277+5246414, the most actinide-enhanced R-II star known |
| title_sort | r process alliance 2mass j09544277 5246414 the most actinide enhanced r ii star known |
| url | https://hdl.handle.net/1721.1/124736 |
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