Problems in the Formation of Neutral Helium Lines in Early Type Stars

1970 ◽  
Vol 1 (7) ◽  
pp. 326-328
Author(s):  
R. W. Simpson
Keyword(s):  
Absorption Coefficient ◽  
Electron Scattering ◽  
Growth Analysis ◽  
Line Profiles ◽  
Early Type ◽  
Line Absorption ◽  
Early Type Stars ◽  
Made In ◽  
The Continuum

The aim of this work is to investigate certain assumptions that have been made in calculating line profiles and equivalent widths of neutral helium lines in early type stars. The effect of electron scattering on the continuum flux is investigated and a curve of growth analysis carried out to study this effect. The theories involved in calculating the line absorption coefficient are also investigated.

Preliminary Observations of Interstellar Sodium D-Line Absorption towards the Carina Nebula

1980 ◽  
Vol 4 (1) ◽  
pp. 95-97 ◽  
Author(s):  
J. B. Whiteoak ◽  
F. F. Gardner
Keyword(s):  
High Resolution ◽  
Hii Regions ◽  
Early Type ◽  
Interstellar Clouds ◽  
Carina Nebula ◽  
Line Absorption ◽  
General Investigation ◽  
Early Type Stars ◽  
Resolution Study

As part of a general investigation of interstellar clouds associated with southern HII regions we have begun a high-resolution study of the sodium D-line absorption in the directions of early-type stars that are likely to be associated with or located behind the clouds.

Hβ Line Profiles for Rapidly Rotating Early- Type Stars.

1965 ◽  
Vol 70 ◽  
pp. 320
Author(s):  
George W., II Collins ◽  
J. Patrick Harrington
Keyword(s):  
Line Profiles ◽  
Early Type ◽  
Early Type Stars

scholarly journals Photoelectric Measures of Hydrogen-line Absorption in Early-type Stars

1961 ◽  
Vol 123 (6) ◽  
pp. 521-539 ◽  
Author(s):  
M. K. V. Bappu ◽  
S. Chandra ◽  
N. B. Sanwal ◽  
S. D. Sinvhal
Keyword(s):  
Early Type ◽  
Hydrogen Line ◽  
Line Absorption ◽  
Early Type Stars

scholarly journals A Study of Main Sequence Early Type Stars

1979 ◽  
Vol 47 ◽  
pp. 483-490
Author(s):  
Ulf Sinnerstad
Keyword(s):  
Main Sequence ◽  
Photometric Study ◽  
Line Profiles ◽  
Early Type ◽  
Fundamental Parameters ◽  
Preliminary Results ◽  
Early Type Stars ◽  
Hydrogen Lines ◽  
Line Strengths

AbstractA spectroscopic and photometric study of 75 normal main sequence B2-B6 stars has been carried out. From the spectra (12 Å/mm, 3700-4800 Å) are determined: equivalent widths of all measurable lines, line profiles of hydrogen lines and v sin i. The photometric work includes besides uvby and β photometry, also photoelectrically determined line strengths of Hα and He I 4471 Å. Some preliminary results concerning the relation between the MK types and the atmospheric fundamental parameters (Teff, log g) of the stars are briefly discussed.

scholarly journals X-Ray Emission-Line Profiles of Three Early-Type Stars Observed with Chandra

2007 ◽  
Vol 59 (1) ◽  
pp. 237-244 ◽  
Author(s):  
Norimasa Yamamoto ◽  
Haruko Takano ◽  
Shunji Kitamoto ◽  
Takayoshi Kohmura
Keyword(s):  
Emission Line ◽  
Line Profiles ◽  
Early Type ◽  
X Ray ◽  
Early Type Stars

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.

Sign in / Sign up

Export Citation Format

Share Document