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The Magellanic Clouds and the Primordial Helium Abundance

Manuel Peimbert Antonio Peimbert
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Abstract

A new determination of the pregalactic helium abundance based on the Magellanic Clouds H II regions is discussed. This determination amounts to Yp = 0.2345 +- 0.0030 and is compared with those derived from giant extragalactic H II regions in systems with extremely low heavy elements content. It is suggested that the higher primordial value derived by other authors from giant H II region complexes could be due to two systematic effects: the presence of neutral hydrogen inside the helium Stromgren sphere and the presence of temperature variations inside the observed volume.

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Manuel Peimbert Antonio Peimbert. 2000-02-05. The Magellanic Clouds and the Primordial Helium Abundance. https://arxiv.org/abs/astro-ph/0002120

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