HE Astrophysics seminar | Mor Rozner (Technion)

Thu, 17/06/202113:00-14:00
Ross Building, Jerusalem, Israel
Title: Origin of Hot & Warm Jupiters from Inflated Eccentric Migration

Abstract: Hot and warm Jupiters (HJs/WJs) are gas-giant planets orbiting their host stars at very short orbital periods (P_HJ < 10 days; 10 < P_WJ < 200 days). Efficient, in-situ formation of gas-giants at such location poses a challenge to current planet-formation theories. Therefore, HJs/WJs are thought to have migrated from an initially farther-out birth-locations, either through early interactions with the gaseous protoplanetary disc (disc-migration) or through migration on eccentric orbits (eccentric-migration), catalyzed by dissipative tidal interactions raised by the star. However, currently suggested migration models encounter major difficulties in reproducing the frequencies and orbital properties of HJs/WJs. Here we show that eccentric-migration can operate on significantly faster timescales than previously thought, when accounting for the evolution of gas-giants radii. In particular, the tidal-force driving the migration, F_Tide is highly sensitive to the planetary structure and radius, (F_Tide ∝ R^5_Planet). Gas-giants are born with large (R_initial >= 2 RJ ) inflated radii and then contract on timescales of few 10^8 − 10^9 year. Therefore, tidal evolution is far more efficient at early times before they contract to the RJ radius assumed for migrating gas-giants in previous models. We self-consistently model the coupled internal and orbital evolution of gas-giants during their eccentric migration, to find that the inflated eccentric migration model leads to rapid migration and formation of HJs in short timescales that could be as short as few Myrs, and reproduce the majority of the observed populations of HJs/WJs, and their relative frequencies.
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Meeting ID: 891 0952 3146

Passcode: 485033