Abstract
The determination of the mass fraction of primordial helium represents a relevant topic in modern astronomy due to its important cosmological implications in the early universe. The classic method for the determination of (Peimbert & Torres-Peimbert, 1974, ApJ, 193, 327) is based on the abundance analysis of extra-galactic H II regions through their emission lines and the extrapolation to zero metallicity. In this work we carried out a new determination of based on measurements of 12 galaxies with HII regions of low metallicity selectedfrom the Sloan Digital Sky Survey catalog among nearly 500 candidate objects.
Through the extrapolation of the relations Y vs. O/H and N/H, we obtain a primordial helium abundance mass fraction = 0.243 +/- 0.004 for the N/H relation. The determination through the relation Y vs. O/H was not successful due to the presence of peculiar oxygen deficient objects with high helium abundance. However, the importance of these objects is such that if the abundances are confirmed to be of true primary origin and are included in the catalog of H II regions found in the literature, then a correspondence between the observational and WMAP values derived for is possible envisaged.
