Formation of primordial atmospheres for growing protoplanetary cores

Context. In order to find life outside the Solar System we first need to understand how terrestrial planets form in different environments. Many terrestrial planets are formed by a conversion process, during which planets lose most of their H₂-rich (primordial) atmospheres. Primordial atmospheres are formed in the early, disk-embedded phase of planet formation, where a protoplanetary core can accumulate gas from the circumstellar disk into a planetary envelope.
Aim. The aim of this thesis is to simulate the formation process of primordial atmospheres and to analyse their formation as a function of core mass, disk lifetime, and orbital radius. In doing so, this study considers cores that have formed at the start of the embedded phase and do not change their mass during atmosphere formation, as well as cores that grow continuously during the embedded phase.
Methods. The formation of primordial atmospheres are described using the equations of radiation-hydrodynamics, which are solved numerically using the adaptive implicit RHD-code (TAPIR). The discretisation of the physical equations is based on finite volumes on a staggered mesh and advective flows are calculated using the second order van Leer flux limiter.
Results. The study considers primordial atmospheres for orbital radii between 0.387 and 1.524 au, and disk lifetimes in the range of 1 - 10 Myr. The atmospheres get more massive for larger orbital radii, larger core masses, and longer lifetimes of the surrounding disk. Atmospheres of cores more massive than a limitating mass M_c,limit at some point enter a runaway collapse, while atmospheres of less massive cores grow smoothly during their entire formation. The core mass limit M_c,limit shrinks with disk lifetime and orbital radius. The smallest value found is M_c,limit = 0.7 M_⊕.