Challanges for stellar pulsation and evolution theory

8 - Stellar Pulsation and Oscillation

That some stars vary in brightness has been known from time immemorial. That this variation is the result of intrinsic changes in the star itself has been known for less than 100 years and the causes of those variations have been understood for less than 30 years. It is not a simple matter to distinguish the light variations resulting from eclipses by a companion from those caused by physical c...

Cepheid models based on self-consistent stellar evolution and pulsation calculations: the right answer?

We have computed stellar evolutionary models for stars in a mass range characteristic of Cepheid variables (3 < m/M < 12) for different metallicities representative of the Galaxy and the Magellanic Clouds populations. The stellar evolution calculations are coupled to a linear non adiabatic stability analysis to get self-consistent mass-period-luminosity relations. The period luminosity relation...

Noise-driven evolution in stellar systems: Theory

We present a theory for describing the evolution of a galaxy caused by stochastic events such as weak mergers, transient spiral structure, orbiting blobs, etc. This noise excites large-scale patterns that drives the evolution of the galactic density profile. In dark-matter haloes, the repeated stochastic perturbations preferentially ring the lowest-order modes of the halo with only a very weak ...

Cepheids: Pulsation, Evolution, Opacity

We describe modeling of the ''beat'' and "bump" Cepheids, using the new radiative opacities. Discrepancies between these models and the evolutionary tracks for stars of appropriate mass are discussed. Finally, we point out some of the difficulties involving the long-period Cepheid sample with periods greater than 20 days.

Stellar Structure and Evolution