Temperature dependence of sodium and ionized calcium resonance lines perturbed by helium

[摘要] Traces of heavy metals in cool DZ white dwarf stars may be attributed to the accretion of circumstellar dust thought to originate from tidal disruption of rocky parent bodies. Spectra of such stars therefore provide a unique opportunity to study the composition of extrasolar planetary systems. The determination of metal abundances from stellar spectra depends on stellar atmospheric parameters and an accurate prior knowledge of the collision broadening of the line profiles by the most common constituents of the stellar atmosphere. For this purpose, we present theoretical absorption spectra of Na and Ca+broadened by He for the conditions prevailing in cool white dwarfs.

[发布机构] Observatoire de Paris, GEPI, CNRS, Avenue de l'Observatoire, 61, Paris; F-75014, France^1;Institut d'Astrophysique, UMR7095, Université Paris VI, 98bis Boulevard Arago, Paris; F-75014, France^2;Centre de Recherche Astrophysique de Lyon, UMR 5574: CNRS, École Normale Supérieure de Lyon, 46 alée d'ltalie, Lyon Cedex 07; F-69364, France^3;Lab. Interdisciplinaire Carnot de Bourgogne, UMR 6303, Université de Bourgogne, Dijon Cedex; 21078, France^4;Institut de Physique de Rennes, Université de Rennes 1, Rennes; F-35042, France^5;Department of Physics and Astronomy, University of Louisville, Louisville; KY; 40292, United States^6

[关键词] Atmospheric parameters;Circumstellar dust;Collision broadening;Metal abundances;Planetary system;Stellar atmospheres;Temperature dependence;Theoretical absorption spectra