Study of sun-like G stars and their exoplanets

Abstract

By employing exoplanetary physical and orbital characteristics, aim of this study is to understand the genesis, dynamics, chemical abundance and magnetic field structure of Sun-like G stars and relationship with their planets. With reasonable constraints on selection of exoplanetary physical characteristics, and by making corrections for stellar rate of mass loss, a power law relationship between initial stellar mass and their exoplanetary mass is obtained that suggests massive stars harbor massive planets. Such a power law relationship is exploited to estimate the initial mass (1.060 0.006)M of the Sun for possible solution of “Faint young Sun paradox” which indeed indicates slightly higher mass compared to present mass. Another unsolved puzzle of solar system is angular momentum problem, viz., compare to Sun most of the angular momentum is concentrated in the solar system planets. By analyzing the exoplanetary data, this study shows that orbital angular momentum of Solar system planets is higher compared to orbital angular momentum of exoplanets. This study also supports the results of Nice and Grand Tack models that propose the idea of outward migration of Jovian planets during early history of Solar system formation. Furthermore, we have examined the influence of stellar metallicity on the host stars mass and exoplanetary physical and orbital characteristics that shows a non-linear relationship. Another important result is most of the planets in single planetary stellar systems are captured from the space and/or inward migration of planets might have played a dominant role in the final architecture of single planetary stellar systems. Finally, with the host star chromospheric activity as a magnetic field proxy, following problems are investigated. At the present epoch, influence of planetary mass on the host star’s magnetic activity is examined and it is found that host star’s magnetic activity is independent of any planetary mass present in the vicinity of the host star. At the early epoch of planetary formation, the role of largescale magnetic field on the planetary formation is examined which suggests that strong magnetic field inhibits more concentration of planetary mass in the protoplanetary disk.