Published online by Cambridge University Press: 07 February 2017
The problem of the adiabatic non-radial oscillations of spherical stars is reviewed and results recalled for a variety of models. The anomalous behaviour of the eigenfunctions for highly condensed models is related to the apparent mobile singularities depending on the eigenvalues. Tables of Q-values are provided to facilitate possible applications to variable stars.
In the case of the gravity modes, the existence of multiple spectra some stable (g+ modes) some unstable (g− modes) if superadiabatic and subadiabatic regions alternate is discussed and the interest of further investigations underlined.
As far as vibrational stability (effects of the non adiabatic terms) is concerned, a general expression is given for the ‘damping coefficient’. The attention is drawn to the possibility for g+ modes of becoming vibrationally unstable under the effect of various factors and in various models, including the Sun where this was advocated as a possibility of relieving the neutrinos difficulty.
Finally the present status of the most obvious candidates among variable stars for non-radial oscillations, the β Canis Majoris stars and the rapid blue variables (white dwarfs) is briefly reviewed.