Science goals and objectives: we propose to attack, mainly through numerical modeling, some major outstanding problems in the core nucleated accretion theory of the formation of the giant planets in…

This is a cooperative agreement awarded by the National Aeronautics and Space Administration (NASA) Shared Services Center to the non-profit Seti Institute. The $333,460.00 contract supports research focused on improving the core nucleated accretion theory for the formation of the giant planets in our solar system. The work will incorporate important physical processes that were previously neglected, providing a more realistic model of giant planet formation and early evolution. Key areas of focus include studying the effects of planetesimal evaporation within the planet's atmosphere and the resulting mixing of atmospheric constituents. This research aims to better understand how these processes may have influenced the internal structure of the giant planets. The Seti Institute has served as a prime contractor supporting NASA's Office of Planetary Protection, and has also conducted astrobiology, planetary science, and astronomy research under federal grants. No set-aside designation is indicated for this award.

Science goals and objectives: we propose to attack, mainly through numerical modeling, some major outstanding problems in the core nucleated accretion theory of the formation of the giant planets in the solar system. This work will account for important physical processes heretofore neglected and thereby provide a much more realistic model for the formation and early evolution of the giant planets. During the early stages of giant planet accretion, with a rocky core of around an earth mass, the basal temperature of the hydrogen atmosphere above this growing core can already exceed a few thousand degrees, sufficient to allow evaporation of accreted planetesimals within the envelope. This may affect the growth of the giant planet, primarily by increasing the mean molecular weight of the envelope (reducing the pressure scale height), and IT may also produce a wider range of possible outcomes for giant planet formation than those previously studied. The consequences may be partially preserved throughout subsequent evolution and influence the internal structure of the giant planets today. To study the effects of this process, we will compute the amount of mixing of the constituents within the planets during their growth. This additional physics will be incorporated into detailed numerical studies of the concurrent accretion of solids and gas, including an improved treatment of interactions of the growing planets with the surrounding protoplanetary disk.