Stellar opacity validations
Abstract
This paper focuses on the radiative transfer in stars where opacities seem to raise problems : β-Cephei and solar-type stars. We first concentrate on the iron bump (log T = 5.25), responsible for β-Cephei pulsations through the κ-mechanism. To discriminate between the different opacity calculations used to predict their oscillations, new well-qualified calculations are used and compared to OP calculations. In parallel with this theoretical work, an experiment has been conducted at LULI 2000 in 2011 on iron and nickel. We show that this extended study pushes for the revision of the tables in the conditions corresponding to the iron bump region, at least for nickel. We will then deal with the Sun case for which we are preparing an opacity experiment on a high-energy laser, in some conditions of the radiative zone (T = [2 - 15 ×10^{6} K] and ρ = [0.2 - 150 g/cm^{3}]). To reach these high temperatures and densities at LTE and validate or not plasma effects and line widths, we are exploring an approach called the Double Ablation Front, driven by plasma radiative effects. The 1D simulations performed with the code CHIC show that with this technique, we could reach conditions equivalent to the conditions of half of the solar radiative zone.
- Publication:
-
SF2A-2014: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics
- Pub Date:
- December 2014
- Bibcode:
- 2014sf2a.conf..487L
- Keywords:
-
- opacity;
- sun;
- massive stars;
- plasma physics