An Origin of Misaligned Planets: Angular Momentum Accretion in Star Formation Process

Presenter: Shu-ichiro INUTSUKA
We explain the primordial origin of misalignment between planet's orbit and host star's rotation from the context of the disk formation. Theoretical and observational investigations have provided convincing evidence for the formation of molecular cloud cores by the gravitational fragmentation of filamentary molecular clouds, which has important implication for the origin of the stellar initial mass function. On the other hand, the size and total angular momentum of a protoplanetary disk are supposed to be related directly to the rotational property of the parental molecular cloud core where the central protostar and surrounding disk are born. Our recent analysis concludes that mass function and angular momentum distribution of molecular cloud core are the natural outcome of transonic turbulence with Kolmogorov spectrum in parental filamentary molecular clouds. The implication of this identification is non-homogeneous angular momentum distribution inside a molecular cloud core. The actual angular momentum accretion onto a young stellar object in the core should create misalignment of disk surrounding the star. We show the probability distribution of the misalignment as a function of disk mass. This finding may explain the origin of misaligned planets created in those disks.