Hydrodynamic simulations of captured protoatmospheres around Earth-like planets

Author(s)
Alexander Stökl, Ernst Dorfi, Helmut Lammer
Abstract

Young terrestrial planets, when they are still embedded in a circumstellar disk, accumulate an atmosphere of nebula gas. The evolution and eventual evaporation of the protoplanetary disk affect the structure and dynamics of the planetary atmosphere. These processes, combined with other mass loss mechanisms, such as thermal escape driven by extreme ultraviolet and soft X-ray radiation (XUV) from the young host star, determine how much of the primary atmosphere, if anything at all, survives into later stages of planetary evolution. Our aim is to explore the structure and the dynamic outflow processes of nebula-accreted atmospheres in dependency on changes in the planetary environment. We integrate stationary hydrostatic models and perform time-dependent dynamical simulations to investigate the effect of a changing nebula environment on the atmospheric structure and the timescales on which the protoatmosphere reacts to these changes. We find that the behavior of the atmospheres strongly depends on the mass of the planetary core. For planets of about Mars-mass the atmospheric structure, and in particular the atmospheric mass, changes drastically and on very short timescales whereas atmospheres around higher mass planets are much more robust and inert.

Organisation(s)
Department of Astrophysics
External organisation(s)
Österreichische Akademie der Wissenschaften (ÖAW)
Journal
Astronomy & Astrophysics
Volume
576
ISSN
0004-6361
DOI
https://doi.org/10.1051/0004-6361/201423638
Publication date
04-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas
Astronomy and Astrophysics, Space and Planetary Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/f51ecea6-8be6-4605-853c-d1f6bc7f9c04