Astronomy and Astrophysics – Astronomy
Scientific paper
May 1979
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1979phdt.........4p&link_type=abstract
Ph.D. Thesis State Univ. of New York, Stony Brook.
Astronomy and Astrophysics
Astronomy
2
Big Bang Cosmology, Helium, Milky Way Galaxy, Abundance, Astronomical Spectroscopy, B Stars, Binary Stars, Interstellar Matter, Spectrograms
Scientific paper
Helium abundances derived from high dispersion spectrograms of 80 early B stars are discussed. These objects are members of seven young clusters and two associations which span a range of galactocentric radius of nearly four kiloparsecs. It is assumed that each cluster is characterized by a unique helium abundance which reflects that of the interstellar medium from which the cluster condensed. An estimate of this abundance can be obtained from the mean of the helium abundance determined from the individual B stars in a cluster. Comparison of the cluster means shows a range in abundances of 086 or = N(He) or = .107. However, the inclusion of undetected spectroscopic binaries may have a substantial effect on the cluster mean helium abundance. A method of indentifying suspected systems in the observed clusters is proposed. A strong upper limit is placed on a possible helium abundance gradient in the Galaxy indicating a mean abundance of N(He)=.097 + or - .002 for B stars. Assuming helium enhancement by nuclear processing of an amount similar to the observed metal enhancement in Population I objects yields YP = .24, within the predicted range of Big Bang cosmology.
No associations
LandOfFree
Helium abundances in young clusters and associations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Helium abundances in young clusters and associations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Helium abundances in young clusters and associations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1702838