Giant Planet Core Formation

Southwest Research Institute, San Antonio TX

Investigators

Abstract

Jupiter and Saturn represent a challenge to theories of planet formation. Being gas giants, they must have formed in less than 10 million years to be able to accrete gas from the solar nebula before it dissipated. The current leading theory for giant planet formation is the core accretion model, in which a large planetary embryo forms first by accretion of solid planetesimals, and subsequently accretes gas when it has grown to approximately 10 Earth masses. However, this model has a weakness, in that the initial accretion of a large embryo is hindered by a variety of physical processes. In this renewed project, the Principal Investigator, a postdoctoral researcher, and collaborators will continue to develop an extensive computer model of core accretion in order to determine whether this theory is viable. The team will perform a series of simulations of the evolution of a system of embryos and planetesimals embedded in the solar nebula. The models will include: (i) direct gravitational interaction of the planetesimals and embryos, (ii) aerodynamic drag on the planetesimals, (iii) migration of the embryos through gravitational interaction with the protoplanetary disk, (iv) embryo fragmentation, (v) the effects of embryos' atmospheres, (vi) the buildup of solids at the snow-line, and (vii) turbulence-driven migration of the embryos. The team's N-body code will be coupled with state-of-the-art models of the solar nebula in order to determine how (ii), (iii) and (vi) change with time. The project is broadly relevant to the history of the Solar System and has implications for Earth?s acquisition of water. The project will support the early career development of a woman scientist. The Principal Investigator will continue his involvement with public outreach and broadcast and print media.