Angular Momentum of Stars and their Planets

Abstract

To understand the distribution of angular momenta between host stars and their planets, we estimate the spin angular momentum (Jspin) of host stars that follow a power law with stellar mass . Similarly, the orbital angular momenta (Lp) of exoplanets are estimated, and the best fit yields a power law, , with the exoplanetary mass . Furthermore, the total (spin and orbital) angular momentum Jtot of the stellar planetary system is computed, and a power law of the form Jtot = is obtained. In addition, an analysis between specific angular momenta (Ip) of planets and planetary masses reveals that specific angular momentum is nonlinearly related with planetary mass in case of multiplanetary systems and is independent of planetary mass in case of single-planetary systems. We find that the probability of detecting Earth-like planets is more likely for host stars that have total angular momentum ≤1041 kg m2 s−1. Finally, a power-law relationship is obtained between exoplanetary masses and their orbital distances in case of multiplanetary systems and, is independent in case of single-planetary systems.