Measuring Hydrogen-to-Helium Ratio in Cool Stars
Abstract
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.
Keywords
Cite
@article{arxiv.2401.09121,
title = {Measuring Hydrogen-to-Helium Ratio in Cool Stars},
author = {B. P. Hema and Gajendra Pandey},
journal= {arXiv preprint arXiv:2401.09121},
year = {2024}
}
Comments
Accepted for publication in Bulletin de la Soci\'et\'e Royale des Sciences de Li\`ege (BSRSL), In press 10 Pages, 3 Figures and 1 Table. arXiv admin note: text overlap with arXiv:1408.1205