The influence of a close secondary star on the planetary formation: The case of γ cephei b

Abstract

The formation of planets around a single star is a complex process that depends on many parameters. Planetary systems with a secondary star too close to the primary star can significantly complicate the process. In this work, we explored the formation of γ Cephei b, a giant planet located in a close binary system, using a hydrodynamic approach. We tested different parameters for the discs and protoplanet in an attempt to reproduce the observed features. We found that in situ formation can reach the observational mass of the planet. Both isothermal and radiative disc conditions exhibited similar planetary evolution. However, our results demonstrated a high planetary eccentricity. To understand this behaviour, we applied secular theory to the γ Cephei system. We found that the system can reproduce the observational and simulated values of eccentricities.