Opacities for stellar envelopes

RADIATIVE OPACITIES AND STEllAR PULSATIONS

Stellar Masers, Circumstellar Envelopes, and Supernova Remnants

This paper reviews recent advances in the study or circumstellar masers and masers found toward supernova remnants. The review is organized by science focus area, including the astrophysics of extended stellar atmospheres, stellar mass-loss processes and outflows, late-type evolved stellar evolution, stellar maser excitation and chemistry, and the use of stellar masers as independent distance e...

Photofluid Instabilities of Hot Stellar Envelopes

Beginning from a relatively simple set of dynamical equations for a fluid permeated by a radiative field strong enough to produce significant forces, we find the structure of plane-parallel equilibria and study their stability to small acoustic disturbances. In doing this, we neglect viscous effects and complications of nongreyness. We find that acoustic instabilities occur over a wide range of...

Laser Action I N Stellar Envelopes

It is shown that in high-temperature stars in which high speed mass loss is occurring, the rapidly recombining plasma in the stellar envelope can act as an amplifying medium. Model calculations for laser action in He 11 1-4686, using the collisional-radiative model, are presented. Menzel's hypothesis of laser action in distended stellar atmospheres is shown to be fully substantiated. The releva...

Accuray of Stellar Opacities and the Solar Abundance Problem

The abundances of some of the most common elements in the Sun has been called into question by recent analysis based on new non-LTE hydrodynamic models. The new abundances of C, N, O, Ne etc. are 30-40% lower than the ’standard’ solar abundances, which were heretofore well established and supported by precise helioseismological observations. A number of recent studies have addressed the issue f...