Mass ejection from the O4f star zeta puppis

Journal Article · Wed Dec 01 00:00:00 EST 1976 · Astrophys. J., Suppl. Ser.; (United States)

DOI:https://doi.org/10.1086/190413· OSTI ID:7230318

Morton, D C

The observed profiles of P Cygni lines and displaced absorption lines in zeta Pup have been compared with calculations based on a parametrized model of an expanding envelope with the ionization equilibrium for solar abundances. Altogether 14 separate profiles in the far-ultraviolet were used, including the resonance lines of C III, C IV, N III, N V, O VI, Si IV, P V, S IV, and S VI, and subordinate lines of C III, N IV, O IV, and O V. The stellar radius R/sub */ occulting the emission region was taken as 20.3 R/sub sun/ from the measured angular diameter, and a terminal velocity v/sub infinity/ = 2660 km s/sup -1/ was adopted from the resonance profiles. Reasonable fits to all profiles were obtained with a line optical depth that varies in the envelope as (1-v/v/sub i/) and a velocity law that can be approximated by v = v/sub infinity/(1-r/sub 0//r)/sup 1///sup 2/ in the region where v>0.25 v/sub infinity/, with r/sub 0/ = 1.25 R/sub */ = 25.4 R/sub sun/. The electron temperature T/sub e/ is relatively constant at 2 x 10/sup 5/ K throughout the envelope, and the electron density varies between 9.1 x 10/sup 10/ cm/sup -3/ at r/R +- =1.31 and 2.3 x 10/sup 8/ at r/R/sub */ = 12.5. The rate of mass ejection is 7.2 ( +- 3.2) x 10/sup -6/ M/sub sun/ yr/sup -1/, which has a kinetic energy of about 0.2 percent of the stellar luminosity. The acceleration can be provided by the radiation from a star with T/sub eff/approx. =50,000 K acting on numerous resonance lines beyond the Lyman limit, particularly lines of O III, O IV, Ne III, Ne V, and Mg V. The model also predicts an electron scattering halo with a radius considerably larger than the true photospheric radius; this halo may account for the unexpectedly large radius measured by the intensity interferometer.

• Research Organization: The Astronomical Institute at Utrecht
• OSTI ID: 7230318
• Journal Information: Astrophys. J., Suppl. Ser.; (United States), Vol. 32:4
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
STARS
MASS TRANSFER
STELLAR ATMOSPHERES
STAR MODELS
ABSORPTION SPECTRA
ELECTRON DENSITY
ELECTRON TEMPERATURE
ENERGY LEVELS
IONIZATION
RADIATION PRESSURE
SPECTRAL FUNCTIONS
STAR EVOLUTION
STELLAR WINDS
ULTRAVIOLET SPECTRA
ATMOSPHERES
FUNCTIONS
MATHEMATICAL MODELS
SPECTRA
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources