Spectroscopic studies of O-type stars. II. Comparison with non-LTE models.

Abstract

view Abstract Citations (152) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectroscopic studies of O-type stars. II. Comparison with non-LTE models. Conti, P. S. Abstract Equivalent widths of strong He I and He ii lines and Hy in a large sample of 0 stars are compared with predictions from the plane-parallel non-LTE models of Auer and Mihalas. There is very good agreement indicating the essential correctness of their models. However, for many stars there is a dramatic difference between the predictions and the observations of A4686 He ii. This is almost certainly the result of neglect of extended-envelope and dynamical effects in these stars. This line is a useful spectroscopic tool to identify stars in which plane-parallel atmospheres are not completely appropriate. The runs of equivalent widths of representative lines of C iii, N iii, 0 iii, and Si iv are also presented for many 0 stars. There is a positive gravity (luminosity) effect for the latter three ions, but model predictions have not yet been made. The presence of the "unidentified" emission lines at AA4486, 4504 correlates well with A4686 He ii tending to emission, and suggests that these lines are formed only in extended envelopes. Subject headings: atmospheres, stellar - early-type stars - emission-line stars - Of stars - radiative transfer - spectrophotometry Publication: The Astrophysical Journal Pub Date: January 1973 DOI: 10.1086/151856 Bibcode: 1973ApJ...179..161C full text sources ADS | data products SIMBAD (126) Related Materials (8) Part 1: 1971ApJ...170..325C Part 3: 1973ApJ...179..181C Part 4: 1974ApJ...187..539C Part 5: 1974ApJ...193..113C Part 6: 1977ApJ...212..728C Part 7: 1977ApJ...213..438C Part 8: 1977ApJ...214..759C Part 9: 1980ApJ...242.1063G