New study of the line profiles of sodium perturbed by H 2

Nicole F. Allard (1, 2) , Fernand Spiegelman (3) , Thierry Leininger (4) , P. Molliere (5)

1 IAP - Institut d'Astrophysique de Paris
2 GEPI - Galaxies, Etoiles, Physique, Instrumentation
3 MAD - Modélisation, Agrégats, Dynamique (LCPQ)
4 GMO - Groupe THEO (LCPQ)
5 Leiden Observatory [Leiden]

The opacity of alkali atoms, most importantly of Na and K, plays a crucial role in the atmospheres of brown dwarfs and exoplanets. We present a comprehensive study of Na-H 2 collisional profiles at temperatures from 500 to 3000 K, the temperatures prevailing in the atmosphere of brown dwarfs and Jupiter-mass planets. The relevant H 2 perturber densities reach several 10 19 cm −3 in hot (T eff 1500 K) Jupiter-mass planets and can exceed 10 20 cm −3 for more massive or cooler objects. Accurate pressure-broadened profiles that are valid at high densities of H 2 should be incorporated into spectral models. Unified profiles of sodium perturbed by molecular hydrogen were calculated in the semi-classical approach using up-to-date molecular data. New Na-H 2 collisional profiles and their effects on the synthetic spectra of brown dwarfs and hot Jupiters computed with petitCODE are presented.

Mots clés: profiles; molecular data; brown dwarfs

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]

Nicole F. Allard, Fernand Spiegelman, Thierry Leininger, P. Molliere. New study of the line profiles of sodium perturbed by H 2. Astronomy and Astrophysics - A&A, 2019, 628 (A120), pp.8. ⟨10.1051/0004-6361/201935593⟩. ⟨hal-02282079⟩