Seven Problems Related to the Determination of the Primordial Helium Abundance

Bibcode
2003ASPC..297...81P
Peimbert, Manuel; Peimbert, Antonio; Luridiana, Valentina; Ruiz, María Teresa
Bibliographical reference

Star Formation Through Time, ASP Conference Proceedings, Vol. 297, held 24-28 September 2002 in Granada, Spain. Edited by Enrique Perez, Rosa M. Gonzalez Delgado and Guillermo Tenorio-Tagle. ISBN: 1-58381-144-3, 2003, p.81

Advertised on:
0
2003
Number of authors
4
IAC number of authors
0
Citations
20
Refereed citations
14
Description
Recent advances on the quest to determine the primordial or pregalactic helium abundance, Yp, are reviewed. There are seven problems affecting the He/H abundance determinations of H II regions that are briefly discussed: the underlying absorption lines in the observed spectra, the ionization, temperature, and density structures of each object, the collisional contribution to the intensity of the He I and H I lines, the optical thickness of the He I lines, and the extrapolation to derive Yp based on the Y and O/H values.
Type
Non-refereed

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