Iron and Nickel spectral opacity calculations in conditions relevant for pulsating stellar envelopes and experiments

D Gilles,L Piau,F Thais,F Gilleron,Q Porcherot,Jean‐Christophe Pain ,Ph Cossé ,F Delahaye,J E Ducret ,T Błeński ,D P Kilcrease ,Joyce A Guzik ,M Busquet,G Faussurier,S Bastiani‐Ceccotti ,Julie A Harris ,S Turck‐Chièze ,N H Magee ,Guillaume Loisel ,C Blancard,C J Zeippen

doi:10.1051/epjconf/20135914003

Abstract

Seismology of stars is strongly developing. To address this question we have formed an international collaboration, OPAC, to perform specific experimental measurements, compare opacity calculations, and improve the opacity calculations in stellar codes [1]. We consider the following opacity codes: SCO, CASSANDRA, STA, OPAS, LEDCOP, OP, SCO-RCG. Their comparison has shown large differences for Fe and Ni in equivalent conditions of envelopes of type II supernova precursors, temperatures between 15 and 40 eV and densities of a few mg/cm3 [2–4]. LEDCOP, OPAS, SCO-RCG structure codes and STA give similar results and differ from OP ones for the lower temperatures and for spectral interval values [3]. In this work we discuss the role of Configuration Interaction (CI) and the influence of the number of used configurations. We present and include in the opacity code comparisons new HULLAC-v9 calculations [5, 6] that include full CI. To illustrate the importance of this effect we compare different CI approximations (modes) available in HULLAC-v9 [7]. These results are compared to previous predictions and to experimental data. Differences with OP results are discussed.

Highlights

We present and include in the opacity code comparisons new HULLAC-v9 calculations [5, 6] that include full Configuration Interaction (CI)
In recent papers [2, 3] we have compared a large number of opacity calculations for experimental conditions relevant for stellar envelope conditions of intermediate mass stars
In this paper we present HULLAC-v9 predictions for two sets of experimental conditions typical of 1/ Da Silva et al experiment on iron [8] and 2/ LULI 2010 experiment first analysis on nickel [2]

Summary

Introduction

We consider the following opacity codes: SCO, CASSANDRA, STA, OPAS, LEDCOP, OP, SCO-RCG. LEDCOP, OPAS, SCO-RCG structure codes and STA give similar results and differ from OP ones for the lower temperatures and for spectral interval values [3]. We present and include in the opacity code comparisons new HULLAC-v9 calculations [5, 6] that include full CI.

Results

Conclusion