Bulletin de la Société Royale des Sciences de Liège

0037-9565 1783-5720

 

sinds 05 februari 2011 :
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Banagere Prakash Hema & Gajendra Pandey

Measuring Hydrogen-to-Helium Ratio in Cool Stars

(Volume 93 - Année 2024 — No 2 - Proceeedings of the 3rd BINA Workshop on the Scientific Potential of the Indo-Belgian Cooperation)
DOI: 10.25518/0037-9565.11726
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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 ω Centauri. The sample selection, observations, methodoloy and results are discussed in detail.

Keywords : Stars: Giants, Chemical abundance, Chemically peculiar

Om dit artikel te citeren:

Banagere Prakash Hema & Gajendra Pandey, «Measuring Hydrogen-to-Helium Ratio in Cool Stars», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 93 - Année 2024, No 2 - Proceeedings of the 3rd BINA Workshop on the Scientific Potential of the Indo-Belgian Cooperation, 395-405 URL : http://popups.ulg.be/0037-9565/index.php?id=11726.

Over : Banagere Prakash Hema

Indian Institute of Astrophysics, Bengaluru, Karnataka 560034, India. Corresponding author: hema.bp@iiap.res.in

Over : Gajendra Pandey

Indian Institute of Astrophysics, Bengaluru, Karnataka 560034, India. Corresponding author: pandey@iiap.res.in