Optical studies of galactic nebulae and of their exciting stars : The role of dust on the radius of the ionized hydrogen sphere
From new observational data, Georgelin, Lortet-Zuckermann and Monnet (1975) and Chopinet and Lortet-Zuckermann (1975) have rediscussed the use of the Zanstra method in order to derive the rate of stellar ultra-violet photons from hot stars and have studied the relation between the excitation of the nebular spectrum and the spectral type of the exciting star. I wish to show here that dust grains mixed within the ionized gas cannot be an efficient competitor with hydrogen atoms for the absorption of stellar Lyman photons, and thus that this mechanism cannot affect significantly the effective temperature scale derived by Georgelin, Lortet-Zuckermann and Monnet.
KeywordsEffective Temperature Spectral Type Excitation Parameter Ionize Hydrogen Efficient Competitor
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