Contributed Talk - Splinter Exoplanets

Thursday, 14 September 2023, 17:00   (H 3007)

Hot Jupiter formation in Dense Star Clusters

Leonard Benkendorff (1), Francesco Flammini Dotti (1), Rainer Spurzem (1), Katja Stock (2), Maxwell Cai (3)
(1) Universität Heidelberg (2) GMV (3) Leiden University

Hot Jupiters (HJ) are defined as Jupiter-mass exoplanets orbiting around their host star with a semi-major axis of less than 0.1 au. It is generally believed that they cannot form near their observed location but migrate inwards. Recent discoveries showed that star clusters are likely to contribute to the formation of HJ. We use NBody6++GPU and LPS to simulate the dynamics of sets of 200 identical planetary systems around Sun-mass stars in dense star clusters with 32 000 and 64 000 members. We use different sets with 3, 4 or 5 planets. We show that close stellar encounters and internal planetary dynamics as well as tidal migration can form HJ in multi-planetary systems. Denser star clusters are more likely to form HJ for planetary systems with close orbiting planets whereas less dense star clusters are more likely to form HJ for planetary systems with planets with a semi-major axis beyond 5 au. Effective (i.e., encounters which strongly perturb orbital elements) close encounters and tidal disruption are factors that narrow down the fraction of HJ. Additionally, our results indicate that young Hot Jupiters with an age of less than 100 Myrs may be obtained in planetary systems with a planet orbiting at initially 1 au in star clusters.