Non-Lte Model Atmospheres. V. Multi-Line Hydrogen-Helium Models for O and Early B Stars

Abstract

view Abstract Citations (79) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Non-Lte Model Atmospheres. V. Multi-Line Hydrogen-Helium Models for O and Early B Stars Mihalas, Dimitri ; Auer, L. H. Abstract Results of calculations of non-LTE model atmospheres including the effects of La, L , L , Ha, Hp, and Pa are presented for models on the range 250000 K < < 50000 K, with log g = 4 and N(He)/ N(H) = 0.10. The non-LTE results suggest a severe breakdown of LTE at T0ff > 350000 K. Substantial changes occur in the far-ultraviolet fluxes; these may be of importance in the interpretation of the excitation of emission nebulae. In the visible, the Balmer jump is significantly increased by non-LTE effects for models with T0ff > 350000 K, which implies large changes in effective temperatures for 0 stars inferred from observations of the Balmer jump. Striking changes occur in the hydrogen-line profiles. Vhen non-LTE effects are included, Ha and Hp are computed to be almost 3 times as strong at 400000 K as in LTE. Pa is found to have an emission core in the highest-temperature models. This result is analogous to the situation at lower temperatures where Ba is computed to go into emission. In both cases the emission core is due to coupling to a rise in surface temperature in the non-LTE models; observations are desirable to test the reality of this predicted effect. Publication: The Astrophysical Journal Pub Date: June 1970 DOI: 10.1086/150503 Bibcode: 1970ApJ...160.1161M full text sources ADS | Related Materials (6) Part 1: 1969ApJ...156..157A Part 2: 1969ApJ...156..681A Part 3: 1969ApJ...158..641A Part 4: 1970ApJ...160..233A Part 6: 1970ApJ...161.1129M Part 7: 1972ApJS...24..193A