The Magellanic Clouds and the Primordial Helium Abundance
arXiv:astro-ph/0002120
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.
arXiv comment10 pages, 1 figure, IAU Symposium 198
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- On the helium content of Galactic globular clusters via the R parameter
- Primordial Lithium Abundance as a Stringent Constraint on the Baryonic Content of the Universe
- Seismic constraints on open clusters