2024/03/12 by Takato Tokuno, Akihiko Fukui, Tokuno, Takato +3
Earth and Planetary Sciences · Environmental Science · #Geophysics and Gravity Measurements #Methane Hydrates and Related Phenomena #Geological and Geophysical Studies
paper · pdf · doi:10.48550/arxiv.2403.07375
We propose a novel method to constrain the tidal quality factor, Q', from an observed non-synchronized star-planet system consisting of a slowly rotating low-mass star and a close-in Jovian planet, taking into account the co-evolution of stellar spin and planetary orbit due to the tidal interaction and the magnetic braking. On the basis of dynamical system theory, the track of the co-evolution of angular momentum from the fast rotator regime for such a system exhibits the existence of a forbidden region in the Ωorb -- Ωspin plane , where Ωspin and Ωorb denote the angular velocity of the stellar spin and planetary orbit, respectively. The forbidden region is determined primarily by the strength of the tidal interaction. By comparing (Ωorb,Ωspin) of a single star-planet system to the forbidden region, we can constrain the tidal quality factor regardless of the evolutionary history of the system. The application of this method to the star-planet system, NGTS-10 -- NGTS-10 b, gives Q' \gtrsim 108, leading to an tight upper bound on the tidal torque. Since this cannot be explained by previous theoretical predictions for non-synchronized star-planet systems, our result requires mechanisms that suppress the tidal interaction in such systems.