Thermal evolution of an early magma ocean in interaction with the atmosphere

Abstract : The thermal evolution of magma oceans produced by collision with giant impactors late in accretion is expected to depend on the composition and structure of the atmosphere through the greenhouse effect of CO2 and H2O released from the magma during its crystallization. In order to constrain the various cooling timescales of the system, we developed a 1D parameterized convection model of a magma ocean coupled with a 1D radiative-convective model of the atmosphere. We conducted a parametric study and described the influences of the initial volatile inventories, the initial depth of the magma ocean and the Sun-planet distance. Our results suggest that a steam atmosphere delays the end of the magma ocean phase by typically 1 Myr. Water vapor condenses to an ocean after 0.1 Myr, 1.5 Myr and 10 Myr for, respectively, Mars, Earth and Venus. This time would be virtually infinite for an Earth-sized planet located at less than 0.66 AU from the Sun. Using a more accurate calculation of opacities, we show that Venus is much closer to this threshold distance than in previous models. So there are conditions such as no water ocean is formed on Venus. Moreover, for Mars and Earth, water ocean formation time scales are shorter than typical time gaps between major impacts. This implies that successive water oceans may have developed during accretion, making easier the loss of their atmospheres by impact erosion. On the other hand, Venus could have remained in the magma ocean stage for most of its accretion.
Type de document :
Article dans une revue
Journal of Geophysical Research. Planets, Wiley-Blackwell, 2013, 118 (6), pp.1155-1176. 〈10.1002/jgre.20068〉
Liste complète des métadonnées

Littérature citée [74 références]  Voir  Masquer  Télécharger

https://hal.archives-ouvertes.fr/hal-00799240
Contributeur : Catherine Cardon <>
Soumis le : samedi 23 avril 2016 - 14:17:36
Dernière modification le : vendredi 16 novembre 2018 - 01:50:54
Document(s) archivé(s) le : mardi 15 novembre 2016 - 10:51:19

Fichier

Lebrun_et_al-2013-Journal_of_G...
Fichiers éditeurs autorisés sur une archive ouverte

Identifiants

Collections

Citation

Thomas Lebrun, Hélène Massol, Eric Chassefière, Anne Davaille, Emmanuel Marcq, et al.. Thermal evolution of an early magma ocean in interaction with the atmosphere. Journal of Geophysical Research. Planets, Wiley-Blackwell, 2013, 118 (6), pp.1155-1176. 〈10.1002/jgre.20068〉. 〈hal-00799240〉

Partager

Métriques

Consultations de la notice

347

Téléchargements de fichiers

89