Astronomy and Astrophysics – Astrophysics
Scientific paper
Mar 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992mnras.255..325p&link_type=abstract
Monthly Notices of the Royal Astronomical Society (ISSN 0035-8711), vol. 255, March 15, 1992, p. 325-345.
Astronomy and Astrophysics
Astrophysics
504
Abundance, Dwarf Galaxies, H Ii Regions, Helium, Nuclear Astrophysics, Wolf-Rayet Stars, Big Bang Cosmology, Emission Spectra, Markarian Galaxies, Maximum Likelihood Estimates, Starburst Galaxies, Stellar Winds
Scientific paper
The paper describes new helium abundance determinations based largely on measurements of suitable H II galaxies discovered in the Palomar, Michigan, Tololo, and Cambridge objective prism surveys and included in the extensive spectrophotometric survey by Terlevich (1991). Maximum-likelihood regression of helium against both oxygen and nitrogen are found to be quite accurately linear up to 10 exp 6, provided that H II galaxies known to have broad WR emission features are excluded; the latter often show upward deviations from the helium abundance found for other objects with the same oxygen and sometimes with the same nitrogen abundance. This supports an earlier suggestion that there may be additional local sources of both helium and nitrogen in the form of winds from Wolf-Rayet stars or their red supergiant progenitors.
Edmunds Michael G.
Pagel Bernard E. J.
Simonson E. A.
Terlevich Roberto Juan
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