Comments on Recent Statistical-Equilibrium Model-Atmosphere Calculations for Early-Type Stars

1968 ◽  
Vol 153 ◽  
pp. 1009 ◽  
Author(s):  
Douglas H. Sampson
Keyword(s):  
Equilibrium Model ◽  
Model Atmosphere ◽  
Statistical Equilibrium ◽  
Early Type ◽  
Early Type Stars

scholarly journals Discovery of weak magnetic fields in early B-type stars

2003 ◽  
Vol 212 ◽  
pp. 202-203 ◽  
Author(s):  
Huib F. Henrichs ◽  
Coralie Neiner ◽  
Vincent C. Geers
Keyword(s):  
Magnetic Properties ◽  
Stellar Wind ◽  
Magnetic Measurements ◽  
Magnetic Phase ◽  
Model Atmosphere ◽  
Early Type ◽  
Chemical Abundance ◽  
Weak Magnetic Fields ◽  
Magnetic Dipole Field ◽  
Early Type Stars

We summarize recent results of magnetic measurements of three bright early B-type stars, β Cep, ζ Cas, and V2052 Oph, which were found to be oblique rotators with a weak magnetic dipole field with typical strength of a few hundred Gauss. From stellar wind studies we could derive their rotational periods very accurately, and match the stellar wind with the magnetic phase. From model atmosphere fits we derive the angles of rotational and magnetic axis. All three stars show some chemical abundance anomaly, presumably associated with the magnetic properties. The stars are also pulsating variables. This is of high asteroseismological interest, since these are the only early-type stars known with observationally determined rotation, pulsation and magnetic properties.

scholarly journals Theoretical Wavelength Dependence of Polarization in Early-Type Stars

1976 ◽  
Vol 70 ◽  
pp. 375-376
Author(s):  
Bernhard M. Haisch ◽  
Joseph P. Cassinelli
Keyword(s):  
Steady State ◽  
Radiation Pressure ◽  
Electron Scattering ◽  
Wavelength Dependence ◽  
Model Atmosphere ◽  
Be Stars ◽  
Early Type ◽  
Steady State Flow ◽  
Early Type Stars ◽  
Rayet Star

We have examined the theoretical wavelength dependence of linear polarization produced by electron scattering and modified by an absorptive opacity in the extended, distorted atmospheres of Be and Wolf-Rayet stars. A model atmosphere representing a Wolf-Rayet star recently calculated by Cassinelli and Hartmann was used. This model takes into consideration the subsonic portions of a radial, steady-state flow together with the requirement of radiative equilibrium. The model was then scaled down in temperature to approximate the cooler Be stars, again assuming radiative equilibrium. There were four models altogether, one WR star, and three Be models. All the atmospheres are quite extended by radiation pressure.

scholarly journals Observations of Strong Stellar Lines with the OAO

1970 ◽  
Vol 36 ◽  
pp. 173-177
Author(s):  
A.D. Code ◽  
R. C. Bless
Keyword(s):  
Preliminary Analysis ◽  
Temperature Scale ◽  
Model Atmosphere ◽  
Astronomical Observatory ◽  
Qualitative Description ◽  
Spectral Interval ◽  
Early Type ◽  
Stellar Temperature ◽  
Early Type Stars

This paper reports on preliminary analysis of spectral scans of early-type stars obtained with the Orbiting Astronomical Observatory. The discussion is confined to the spectra of 50 stars observed with a resolution of approximately 10 Å over the spectral interval from 1050 Å to 2000 Å. Following a qualitative description of the spectra, observed equivalent widths of the Siiv (1400 Å) and Civ (1550 Å) lines are compared with model atmosphere calculations. The results suggest an upward revision of the stellar temperature scale for stars earlier than B3 V.

scholarly journals Model atmosphere and kinematical analyses of early-type stars from the Edinburgh--Cape Survey

2001 ◽  
Vol 324 (3) ◽  
pp. 747-756 ◽  
Author(s):  
H. R. M. Magee ◽  
P. L. Dufton ◽  
F. P. Keenan ◽  
W. R. J. Rolleston ◽  
D. Kilkenny ◽  
...  
Keyword(s):  
Model Atmosphere ◽  
Early Type ◽  
Early Type Stars
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