2021-07-07

Stellar mass dependence of the habitable zone planetary systems formed by giant impacts

speaker: Haruka Hoshino

Abstract:

Recent exoplanet surveys revealed that for solar-type stars close-in super-Earths are ubiquitous and many of them are in multi-planet systems. These systems are more compact than the solar system’s terrestrial planets. Ongoing and future exoplanet observations will find more planets around low-mass stars. However, there are not many theoretical studies on the formation of such planets around low-mass stars. Now is the time to clarify the dependence of the stellar mass on planet formation. 
We investigate the effect of the stellar mass on the architecture of planetary systems. We perform N-body simulations of the giant impact stage around different stellar masses. Using the minimum-mass extrasolar nebula model, we set the isolation mass of protoplanets and distribute them around habitable zone. We follow the evolution for 200 million orbital periods of the habitable zone inner edge. We find that the eccentricity and inclination of orbits and the orbital separation of adjacent planets increase with the stellar mass. The results can be used to predict the number of planets in the habitable zone from the orbital separation.