Abundance determinations in H II regions - A critical analysis of two empirical methods

Details Abundance determinations in H II regions - A critical analysis of two empirical methods Abundance determinations in H II regions - A critical analysis of two empirical methods

Jan 1981

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1981a%26a....93..362s&link_type=abstract

Astronomy and Astrophysics, vol. 93, no. 1-2, Jan. 1981, p. 362-369.

Astronomy and Astrophysics

Astrophysics

27

Abundance, Electron Energy, Emission Spectra, Galactic Nuclei, H Ii Regions, Spiral Galaxies, H Beta Line, Nebulae, Nitrogen, Oxygen Spectra, Photoionization

Scientific paper

The bases of the empirical methods proposed by Alloin et al. (1979) and Pagel et al. (1979) for determining elemental abundances in H II regions for which a direct estimate of the electron temperature is not available are examined in light of the photoionized models of H II regions derived by Stasińska. The empirical relations on which the methods are based are discussed, with attention given to the dependence of the reddening-free forbidden O III/forbidden N II ratio used by Alloin et al. and the ratio of the sum of forbidden O II and forbidden O III lines to the H beta line on electron temperature. The methods are then applied to abundance determinations for a wide sample of H II regions, and it is shown that the two approaches provide abundance values which are in agreement to within a factor of three for most objects except galactic nuclei, for which N/H and O/H ratios differ by a factor of up to 10. An observed scatter in the N/O ratio as a function of the O/H ratio is shown to invalidate the Alloin method in this case, and it is concluded that the method of Pagel et al. may exhibit a slight advantage for giant H II regions with relatively high abundances.

Affiliated with

Also associated with

No associations

Rating

Abundance determinations in H II regions - A critical analysis of two empirical methods 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 Abundance determinations in H II regions - A critical analysis of two empirical methods, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Abundance determinations in H II regions - A critical analysis of two empirical methods will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1050762