The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo
The recent detection of a binary neutron star merger and the clear evidence of the decay of radioactive material observed in this event have, after 60 years of effort, provided an astrophysical site for the rapid neutron-capture (r-) process which is responsible for the production of the heaviest el...
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| Format: | Article |
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American Astronomical Society
2020
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| Online Access: | https://hdl.handle.net/1721.1/124738 |
| _version_ | 1826202207923470336 |
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| author | Hansen, Terese T. Holmbeck, Erika M. Beers, Timothy C. Placco, Vinicius M. Roederer, Ian U. Frebel, Anna Sakari, Charli M. Simon, Joshua D. Thompson, Ian B. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Hansen, Terese T. Holmbeck, Erika M. Beers, Timothy C. Placco, Vinicius M. Roederer, Ian U. Frebel, Anna Sakari, Charli M. Simon, Joshua D. Thompson, Ian B. |
| author_sort | Hansen, Terese T. |
| collection | MIT |
| description | The recent detection of a binary neutron star merger and the clear evidence of the decay of radioactive material observed in this event have, after 60 years of effort, provided an astrophysical site for the rapid neutron-capture (r-) process which is responsible for the production of the heaviest elements in our universe. However, observations of metal-poor stars with highly enhanced r-process elements have revealed abundance patterns suggesting that multiple sites may be involved. To address this issue, and to advance our understanding of the r-process, we have initiated an extensive search for bright (V < 13.5), very metal-poor ([Fe/H] < -2) stars in the Milky Way halo exhibiting strongly enhanced r-process signatures. This paper presents the first sample collected in the southern hemisphere using the echelle spectrograph on du Pont 2.5 m telescope at Las Campanas Observatory. We have observed and analyzed 107 stars with -3.13 < [Fe/H] < -0.79. Of those, 12 stars are strongly enhanced in heavy r-process elements (r-II), 42 stars show moderate enhancements of heavy r-process material (r-I), and 20 stars exhibit low abundances of the heavy r-process elements and higher abundances of the light r-process elements relative to the heavy ones (limited-r). This search is more successful at finding r-process-enhanced stars compared to previous searches, primarily due to a refined target selection procedure that focuses on red giants. ©2018 |
| first_indexed | 2024-09-23T12:03:53Z |
| format | Article |
| id | mit-1721.1/124738 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T12:03:53Z |
| publishDate | 2020 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1247382022-10-01T07:55:07Z The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo Hansen, Terese T. Holmbeck, Erika M. Beers, Timothy C. Placco, Vinicius M. Roederer, Ian U. Frebel, Anna Sakari, Charli M. Simon, Joshua D. Thompson, Ian B. Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research The recent detection of a binary neutron star merger and the clear evidence of the decay of radioactive material observed in this event have, after 60 years of effort, provided an astrophysical site for the rapid neutron-capture (r-) process which is responsible for the production of the heaviest elements in our universe. However, observations of metal-poor stars with highly enhanced r-process elements have revealed abundance patterns suggesting that multiple sites may be involved. To address this issue, and to advance our understanding of the r-process, we have initiated an extensive search for bright (V < 13.5), very metal-poor ([Fe/H] < -2) stars in the Milky Way halo exhibiting strongly enhanced r-process signatures. This paper presents the first sample collected in the southern hemisphere using the echelle spectrograph on du Pont 2.5 m telescope at Las Campanas Observatory. We have observed and analyzed 107 stars with -3.13 < [Fe/H] < -0.79. Of those, 12 stars are strongly enhanced in heavy r-process elements (r-II), 42 stars show moderate enhancements of heavy r-process material (r-I), and 20 stars exhibit low abundances of the heavy r-process elements and higher abundances of the light r-process elements relative to the heavy ones (limited-r). This search is more successful at finding r-process-enhanced stars compared to previous searches, primarily due to a refined target selection procedure that focuses on red giants. ©2018 NSF (grant no. PHY 14-30152) NSF CAREER (grant no. AST1255160) NSF (grant no. AST-1108811) NSF (grant no. AST-1714873) 2020-04-17T20:14:35Z 2020-04-17T20:14:35Z 2018-05 2018-02 2019-03-22T15:53:47Z Article http://purl.org/eprint/type/JournalArticle 1538-4357 https://hdl.handle.net/1721.1/124738 Hansen, Terese T., et al., "The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo." Astrophysical journal 858, 2 (May 2018): no. 92 doi 10.3847/1538-4357/AABACC ©2018 Author(s) 10.3847/1538-4357/AABACC 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 | Hansen, Terese T. Holmbeck, Erika M. Beers, Timothy C. Placco, Vinicius M. Roederer, Ian U. Frebel, Anna Sakari, Charli M. Simon, Joshua D. Thompson, Ian B. The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo |
| title | The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo |
| title_full | The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo |
| title_fullStr | The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo |
| title_full_unstemmed | The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo |
| title_short | The R-process Alliance: first release from the southern search for R-process-enhanced stars in the galactic halo |
| title_sort | r process alliance first release from the southern search for r process enhanced stars in the galactic halo |
| url | https://hdl.handle.net/1721.1/124738 |
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