Theory of radiatively driven stellar winds. II. The line acceleration

Journal Article · Sun Aug 01 04:00:00 EDT 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160166· OSTI ID:6807243

Abbott, D C

Numerical values of the radiation pressure on spectral lines are presented for the envelopes of stars with type O--G, and with any luminosity, metallicity, or velocity structure. The line acceleration was calculated using a tabulation of atomic lines that is complete for the elements H--Zn. The line acceleration is remarkably constant over the temperature range 50,000> or =T/sub eff/> or =10,000 K, but drops off sharply for cooler stars. The anomalous ionization observed in OB stars decreases the acceleration by up to a factor of 2 from radiative equilibrium values. More than one-half of the acceleration comes from lines whose frequencies overlap with those of neighboring lines at some point in the wind. Line blanketing of the continuum flux by the wind becomes significant for mass loss rates exceeding approx.10/sup -6/ M/sub sun/ yr/sup -1/. The predicted and observed mass loss rates are in complete agreement for the OB stars, and we conclude that radiation pressure is the dominant mechanism driving the winds from these stars. The mass loss rates of Wolf-Rayet stars are not explained by these models, even accounting for the effects of chemical enrichment on the line acceleration. Radiation-driven mass loss is still significant in F and G supergiants, but the predicted rates are smaller than for OBA supergiants of comparable luminosity. The predicted mass loss rate scales nearly linearly with metallicity, with obvious consequences for stellar systems formed in regions of very high, or very low, metallicity. Subject headings: stars: early-type: stars: mass loss: stars: supergiants: stars: winds: stars: Wolf-Rayet

• Research Organization: Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards
• OSTI ID: 6807243
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 259:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CHEMICAL COMPOSITION
FUNCTIONS
GIANT STARS
IONIZATION
MAIN SEQUENCE STARS
MATHEMATICAL MODELS
MATHEMATICS
NUMERICAL ANALYSIS
RADIATION FLUX
RADIATION PRESSURE
RADIATION TRANSPORT
SPECTRA
SPECTRAL FUNCTIONS
STAR MODELS
STARS
STELLAR ATMOSPHERES
STELLAR WINDS
SUPERGIANT STARS
TRANSPORT THEORY
WOLF-RAYET STARS