4 research outputs found
Hydrodynamic simulations of captured protoatmospheres around Earth-like planets
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