Seven problems related to the determination of the primordial helium abundance
Astrophysics
2007-05-23 v1
Abstract
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.
Keywords
Cite
@article{arxiv.astro-ph/0211497,
title = {Seven problems related to the determination of the primordial helium abundance},
author = {Manuel Peimbert and Antonio Peimbert and Valentina Luridiana and Maria Teresa Ruiz},
journal= {arXiv preprint arXiv:astro-ph/0211497},
year = {2007}
}
Comments
10 pages. Conference on Star Formation through Time (ASP Conference Series)