Theoretical H II region models - The effects of stellar atmosphere models

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Astrophysical Journal, Supplement Series; (United States)

DOI:https://doi.org/10.1086/191586· OSTI ID:5318100

Evans, I N ^[1]

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1. Space Telescope Science Institute, Baltimore, MD (USA)

Several grids of theoretical H II region models are computed by photoionization modeling in order to determine the extent to which the choice of the ionizing stellar atmosphere model affects the calibration of emission-line diagnostic diagrams of Evans and Dopita (1985) and the semiempirical H II region abundance sequence calibration of Evans and Dopita. Emission-line diagnostic diagrams are presented and compared for model nebulae ionized by Hummer and Mihalas (1970) unblanketed LTE atmospheres, Kurucz (1979) line-blanketed LTE atmospheres, Mihalas (1972) unblanketed non-LTE, and a truncated blackbody spectrum. The models demonstrate that for solar nebular and atmospheric abundances, there are only minor differences between H II models ionized by the Hummer and Mihalas atmospheres. The unblanketed non-LTE stellar atmosphere models of Mihalas and truncated blackbody spectra are shown to be unsuitable for general H II region modelling. 38 refs.

• OSTI ID: 5318100
• Journal Information: Astrophysical Journal, Supplement Series; (United States), Journal Name: Astrophysical Journal, Supplement Series; (United States) Vol. 76; ISSN APJSA; ISSN 0067-0049
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ATMOSPHERES
COMPARATIVE EVALUATIONS
COSMIC RADIO SOURCES
ELEMENT ABUNDANCE
EQUILIBRIUM
EVALUATION
H2 REGIONS
IONIZATION
LTE
MATHEMATICAL MODELS
PHOTOIONIZATION
STELLAR ATMOSPHERES