Ds. Balser et al., THE COSMIC ABUNDANCE OF HE-3 .3. IMPROVED LINE PARAMETERS FOR SELECTED SOURCES, The Astrophysical journal, 430(2), 1994, pp. 667-681
We report on our progress in determining the cosmic abundance of He-3.
The abundances are derived from observations of the 8.665 GHz hyperfi
ne line of He-3+ in H II regions. Despite observational challenges we
have measured the line to high enough precision in some H II regions t
hat the line parameters are no longer the limiting factor in the accur
acy of the abundance determinations. We find abundances ranging from H
e-3/H approximately 1-4 x 10(-5). Since the abundance pattern does not
fit that expected from the overall chemical evolution of the Galaxy,
we suggest local enrichment of some H II regions, perhaps from Wolf-Ra
yet winds. If averaged over an initial mass function stars are not a n
et sink for He-3, then our lowest abundance source places a lower limi
t on the cosmological parameter eta, the baryon-to-photon ratio. The H
e-3 lower limit is about the same as the upper limit from H-2, He-4, a
nd Li-7, eta approximately 4 x 10(10).