Influence of a magnetic field on the pulsational stability of stars

1979 ◽  
Vol 229 ◽  
pp. 1023 ◽  
Author(s):  
R. Strothers
Keyword(s):  
Magnetic Field ◽  
Stability Of Stars ◽  
Pulsational Stability

Pulsational Stability of Stars in Thermal Imbalance

1973 ◽  
Vol 182 ◽  
pp. 885 ◽  
Author(s):  
J. P. Cox ◽  
C. J. Hansen ◽  
William R. Davey
Keyword(s):  
Stability Of Stars ◽  
Thermal Imbalance ◽  
Pulsational Stability

Influence of Convection on the Pulsational Stability of Stars

1981 ◽  
Vol 93 ◽  
pp. 278-279
Author(s):  
Y. Osaki ◽  
G. Gonczi
Keyword(s):  
Time Dependent ◽  
Phase Lag ◽  
Instability Strip ◽  
Convective Flux ◽  
Local Character ◽  
Spatial Oscillations ◽  
Stability Of Stars ◽  
Mixing Length Theory ◽  
Astronomy And Astrophysics ◽  
Pulsational Stability

Influence of convection on the pulsational stability of stars is examined based on Unno's (1967) theory of time-dependent convection. This theory is an extension of Vitense's local mixing-length theory of convection to the time-dependent problem. The equations of linear non-adiabatic pulsations, which include the thermal interaction between convection and pulsation, have been solved numerically on a series of Cepheid models. It is found that the thermal eigenfunctions (of δ T/T and δ L/L) exhibit spatial oscillations with short wavelength in cool stellar models where the energy is mostly transported by convection. This phenomenon of spatial oscillations is interpreted, and it is shown that they arise because of the phase lag of the convective flux to pulsation and they are related to the local character of the convection theory. It is found that the spatial oscillations play a determinant role in the pulsational stability in the region of the red edge of the Cepheid instability strip, as far as the thermal convection-pulsation coupling is concerned. The details of this study have been pulbished in Astronomy and Astrophysics.

Magnetic-field strengths from optical polarization data

1967 ◽  
Vol 31 ◽  
pp. 381-383
Author(s):  
J. M. Greenberg
Keyword(s):  
Magnetic Field ◽  
Optical Polarization ◽  
Polarization Data ◽  
Term Model ◽  
Source Of Information ◽  
Field Strengths

Van de Hulst (Paper 64, Table 1) has marked optical polarization as a questionable or marginal source of information concerning magnetic field strengths. Rather than arguing about this–I should rate this method asq+-, or quarrelling about the term ‘model-sensitive results’, I wish to stress the historical point that as recently as two years ago there were still some who questioned that optical polarization was definitely due to magnetically-oriented interstellar particles.

Sign in / Sign up

Export Citation Format

Share Document