Title of article :
Measurements of 4He in metal-poor extragalactic H ii regions: the primordial Helium abundance and the ΔY/ΔO ratio
Author/Authors :
Manuel Peimbert، نويسنده , , A. Peimbert، نويسنده , , L. Carigi، نويسنده , , V. Luridiana، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2009
Abstract :
We present a review on the determination of the primordial helium abundance Yp , based on the study of hydrogen and helium recombination lines in extragalactic H ii regions. We also discuss the observational determinations of the increase of helium to the increase of oxygen by mass ΔY/ΔO, and compare them with predictions based on models of galactic chemical evolution.
Keywords :
H II regions , irregular , early universe , ISM: abundances , Galaxy: disk , Evolution , galaxies: abundances
Journal title :
Proceedings of the International Astronomical Union
Journal title :
Proceedings of the International Astronomical Union
