Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H]
We present a chemical abundance analysis of the faint halo metal-poor main-sequence star J0023+0307, with [Fe/H] <-6.3, based on a high-resolution (R ∼ 35,000) Magellan/MIKE spectrum. The star was originally found to have [Fe/H] <-6.6 based on a Ca ii K measurement in an R ∼ 2500 spectrum. No...
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| Format: | Article |
| Language: | English |
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American Astronomical Society
2020
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| Online Access: | https://hdl.handle.net/1721.1/128722 |
| _version_ | 1826197490856099840 |
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| author | Frebel, Anna L. Ezzeddine, Rana Chiti, Anirudh |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Frebel, Anna L. Ezzeddine, Rana Chiti, Anirudh |
| author_sort | Frebel, Anna L. |
| collection | MIT |
| description | We present a chemical abundance analysis of the faint halo metal-poor main-sequence star J0023+0307, with [Fe/H] <-6.3, based on a high-resolution (R ∼ 35,000) Magellan/MIKE spectrum. The star was originally found to have [Fe/H] <-6.6 based on a Ca ii K measurement in an R ∼ 2500 spectrum. No iron lines could be detected in our MIKE spectrum. Spectral lines of Li, C, Na, Mg, Al, Si, and Ca were detected. The Li abundance is close to the Spite Plateau, logϵ(Li) = 1.7, not unlike that of other metal-poor stars, although in stark contrast to the extremely low value found, e.g., in HE 1327-2326 at a similar [Fe/H] value. The carbon G-band is detected and indicates strong C-enhancement, as is typical for stars with low Fe abundances. Elements from Na through Si show a strong odd-even effect, and J0023+0307 displays the second-lowest known [Ca/H] abundance. Overall, the abundance pattern of J0023+0307 suggests that it is a second-generation star that formed from gas enriched by a massive Population III first star exploding as a fallback supernova. The inferred dilution mass of the ejecta is 10 5±0.5 M o of hydrogen, strongly suggesting J0023+0307 formed in a recollapsed minihalo. J0023+0307 is likely very old because it has a very eccentric orbit with a pericenter in the Galactic bulge. |
| first_indexed | 2024-09-23T10:48:48Z |
| format | Article |
| id | mit-1721.1/128722 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T10:48:48Z |
| publishDate | 2020 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1287222022-09-30T23:12:42Z Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] Frebel, Anna L. Ezzeddine, Rana Chiti, Anirudh Massachusetts Institute of Technology. Department of Physics We present a chemical abundance analysis of the faint halo metal-poor main-sequence star J0023+0307, with [Fe/H] <-6.3, based on a high-resolution (R ∼ 35,000) Magellan/MIKE spectrum. The star was originally found to have [Fe/H] <-6.6 based on a Ca ii K measurement in an R ∼ 2500 spectrum. No iron lines could be detected in our MIKE spectrum. Spectral lines of Li, C, Na, Mg, Al, Si, and Ca were detected. The Li abundance is close to the Spite Plateau, logϵ(Li) = 1.7, not unlike that of other metal-poor stars, although in stark contrast to the extremely low value found, e.g., in HE 1327-2326 at a similar [Fe/H] value. The carbon G-band is detected and indicates strong C-enhancement, as is typical for stars with low Fe abundances. Elements from Na through Si show a strong odd-even effect, and J0023+0307 displays the second-lowest known [Ca/H] abundance. Overall, the abundance pattern of J0023+0307 suggests that it is a second-generation star that formed from gas enriched by a massive Population III first star exploding as a fallback supernova. The inferred dilution mass of the ejecta is 10 5±0.5 M o of hydrogen, strongly suggesting J0023+0307 formed in a recollapsed minihalo. J0023+0307 is likely very old because it has a very eccentric orbit with a pericenter in the Galactic bulge. National Science Foundation (U.S.). Faculty Early Career Development Program (Grant AST-1255160) National Science Foundation (U.S.) (Grant 1716251) National Science Foundation (U.S.) (Grant PHY-1430152(JINA-CEE) 2020-12-03T18:32:06Z 2020-12-03T18:32:06Z 2019-01 2018-10 2020-10-23T13:25:41Z Article http://purl.org/eprint/type/JournalArticle 0004-637X https://hdl.handle.net/1721.1/128722 Frebel, Anna et al. “Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H].” Astrophysical Journal, 871, 2 (January 2019): 146 © 2019 The Author(s) en 10.3847/1538-4357/AAE848 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 | Frebel, Anna L. Ezzeddine, Rana Chiti, Anirudh Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] |
| title | Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] |
| title_full | Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] |
| title_fullStr | Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] |
| title_full_unstemmed | Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] |
| title_short | Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] |
| title_sort | chemical abundance signature of j0023 0307 a second generation main sequence star with fe h |
| url | https://hdl.handle.net/1721.1/128722 |
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