R-process-rich Stellar Streams in the Milky Way*
<jats:title>Abstract</jats:title> <jats:p>We present high-resolution Magellan/MIKE spectra of 22 bright (9 < <jats:italic>V</jats:italic> < 13.5) metal-poor stars (−3.18 < [Fe/H] < −1.37) in three different stellar streams, th...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
American Astronomical Society
2022
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| Online Access: | https://hdl.handle.net/1721.1/141811 |
| _version_ | 1826209350023118848 |
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| author | Gull, Maude Frebel, Anna Hinojosa, Karina Roederer, Ian U Ji, Alexander P Brauer, Kaley |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Gull, Maude Frebel, Anna Hinojosa, Karina Roederer, Ian U Ji, Alexander P Brauer, Kaley |
| author_sort | Gull, Maude |
| collection | MIT |
| description | <jats:title>Abstract</jats:title>
<jats:p>We present high-resolution Magellan/MIKE spectra of 22 bright (9 < <jats:italic>V</jats:italic> < 13.5) metal-poor stars (−3.18 < [Fe/H] < −1.37) in three different stellar streams, the Helmi debris stream, the Helmi trail stream, and the <jats:italic>ω</jats:italic> Centauri progenitor stream. We augment our Helmi debris sample with results for 10 stars by Roederer et al. for a total of 32 stars. Detailed chemical abundances of light elements as well as heavy neutron-capture elements have been determined for our 22 stars. All three streams contain carbon-enhanced stars. For 13 stars, neutron-capture element lines were detectable, and they all show signatures in agreement with the scaled solar <jats:italic>r</jats:italic>-process pattern, albeit with a large spread of −0.5 < [Eu/Fe] < +1.3. Eight of these stars show an additional small <jats:italic>s</jats:italic>-process contribution superposed onto their <jats:italic>r</jats:italic>-process pattern. This could be discerned because of the relatively high signal-to-noise ratio of the spectra given that the stars are close by in the halo. Our results suggest that the progenitors of these streams experienced one or more <jats:italic>r</jats:italic>-process events early on, such as a neutron star merger or another prolific <jats:italic>r</jats:italic>-process source. This widely enriched these host systems before their accretion by the Milky Way. The small <jats:italic>s</jats:italic>-process contribution suggests the presence of asymptotic giant branch stars and associated local (inhomogeneous) enrichment as part of the ongoing chemical evolution by low-mass stars. Stars in stellar streams may thus be a promising avenue for studying the detailed history of large dwarf galaxies and their role in halo assembly with easily accessible targets for high-quality spectra of many stars.</jats:p> |
| first_indexed | 2024-09-23T14:21:28Z |
| format | Article |
| id | mit-1721.1/141811 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T14:21:28Z |
| publishDate | 2022 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1418112023-08-07T18:28:14Z R-process-rich Stellar Streams in the Milky Way* Gull, Maude Frebel, Anna Hinojosa, Karina Roederer, Ian U Ji, Alexander P Brauer, Kaley Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research <jats:title>Abstract</jats:title> <jats:p>We present high-resolution Magellan/MIKE spectra of 22 bright (9 < <jats:italic>V</jats:italic> < 13.5) metal-poor stars (−3.18 < [Fe/H] < −1.37) in three different stellar streams, the Helmi debris stream, the Helmi trail stream, and the <jats:italic>ω</jats:italic> Centauri progenitor stream. We augment our Helmi debris sample with results for 10 stars by Roederer et al. for a total of 32 stars. Detailed chemical abundances of light elements as well as heavy neutron-capture elements have been determined for our 22 stars. All three streams contain carbon-enhanced stars. For 13 stars, neutron-capture element lines were detectable, and they all show signatures in agreement with the scaled solar <jats:italic>r</jats:italic>-process pattern, albeit with a large spread of −0.5 < [Eu/Fe] < +1.3. Eight of these stars show an additional small <jats:italic>s</jats:italic>-process contribution superposed onto their <jats:italic>r</jats:italic>-process pattern. This could be discerned because of the relatively high signal-to-noise ratio of the spectra given that the stars are close by in the halo. Our results suggest that the progenitors of these streams experienced one or more <jats:italic>r</jats:italic>-process events early on, such as a neutron star merger or another prolific <jats:italic>r</jats:italic>-process source. This widely enriched these host systems before their accretion by the Milky Way. The small <jats:italic>s</jats:italic>-process contribution suggests the presence of asymptotic giant branch stars and associated local (inhomogeneous) enrichment as part of the ongoing chemical evolution by low-mass stars. Stars in stellar streams may thus be a promising avenue for studying the detailed history of large dwarf galaxies and their role in halo assembly with easily accessible targets for high-quality spectra of many stars.</jats:p> 2022-04-08T19:04:49Z 2022-04-08T19:04:49Z 2021 2022-04-08T19:00:37Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/141811 Gull, Maude, Frebel, Anna, Hinojosa, Karina, Roederer, Ian U, Ji, Alexander P et al. 2021. "R-process-rich Stellar Streams in the Milky Way*." Astrophysical Journal, 912 (1). en 10.3847/1538-4357/ABEA1A 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 American Astronomical Society |
| spellingShingle | Gull, Maude Frebel, Anna Hinojosa, Karina Roederer, Ian U Ji, Alexander P Brauer, Kaley R-process-rich Stellar Streams in the Milky Way* |
| title | R-process-rich Stellar Streams in the Milky Way* |
| title_full | R-process-rich Stellar Streams in the Milky Way* |
| title_fullStr | R-process-rich Stellar Streams in the Milky Way* |
| title_full_unstemmed | R-process-rich Stellar Streams in the Milky Way* |
| title_short | R-process-rich Stellar Streams in the Milky Way* |
| title_sort | r process rich stellar streams in the milky way |
| url | https://hdl.handle.net/1721.1/141811 |
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