Measuring Hydrogen-to-Helium Ratio in Cool Stars
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arXiv
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| Autores principales: | , |
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| Formato: | Preprint |
| Publicado: |
2024
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| _version_ | 1866929213007724544 |
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| author | Hema, B. P. Pandey, Gajendra |
| author_facet | Hema, B. P. Pandey, Gajendra |
| contents | Conventionally, the helium-to-hydrogen ratio for the stars are adopted to be 0.1, as standard, unless, the stars are severely deficient in hydrogen like in RCB-class, or the stars' helium abundance is accurately measured using He I transitions in warm/hotter stars. In our study, the small change in helium-to-hydrogen ratio (from standard value, 0.1) in normal giants were detected from the large difference (> 0.3 dex) in the Mg-abundance measured from Mg I lines and the subordinate lines of (0,0) MgH band. These are the stars that are mildly hydrogen-deficient/He-enhanced. Such stars were spectroscopically discovered for the first time among giants of the globular cluster Omega Centauri. The sample selection, observations, methodology and results are discussed in detail. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_09121 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Measuring Hydrogen-to-Helium Ratio in Cool Stars Hema, B. P. Pandey, Gajendra Solar and Stellar Astrophysics Conventionally, the helium-to-hydrogen ratio for the stars are adopted to be 0.1, as standard, unless, the stars are severely deficient in hydrogen like in RCB-class, or the stars' helium abundance is accurately measured using He I transitions in warm/hotter stars. In our study, the small change in helium-to-hydrogen ratio (from standard value, 0.1) in normal giants were detected from the large difference (> 0.3 dex) in the Mg-abundance measured from Mg I lines and the subordinate lines of (0,0) MgH band. These are the stars that are mildly hydrogen-deficient/He-enhanced. Such stars were spectroscopically discovered for the first time among giants of the globular cluster Omega Centauri. The sample selection, observations, methodology and results are discussed in detail. |
| title | Measuring Hydrogen-to-Helium Ratio in Cool Stars |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2401.09121 |