Disentangling the stellar inclination of transiting planetary systems: Fully analytic approach to the RossiterMcLaughlin effect incorporating the stellar differential rotation
Abstract
The RossiterMcLaughlin (RM) effect has been widely used to estimate the skyprojected spinorbit angle, λ, of transiting planetary systems. Most of the previous analysis assumes that the host stars are rigid rotators in which the amplitude of the RM velocity anomaly is proportional to v_{⋆} sin i_{⋆}. When their latitudinal differential rotation is taken into account, one can break the degeneracy, and determine separately the equatorial rotation velocity v_{⋆} and the inclination i_{⋆} of the host star. We derive a fully analytic approximate formula for the RM effect adopting a parametrized model for the stellar differential rotation. For those stars that exhibit a differential rotation similar to that of the Sun, the corresponding RM velocity modulation amounts to several m s^{1}. We conclude that the latitudinal differential rotation offers a method to estimate i_{⋆}, and thus the full spinorbit angle ψ, from the RM data analysis alone.
 Publication:

Publications of the Astronomical Society of Japan
 Pub Date:
 December 2021
 DOI:
 10.1093/pasj/psab102
 arXiv:
 arXiv:2110.02561
 Bibcode:
 2021PASJ...73.1656S
 Keywords:

 planetary systems;
 planets and satellites: formation;
 planets and satellites: general;
 stars: general;
 Astrophysics  Earth and Planetary Astrophysics;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 20 pages, 11 figures, accepted for publication in PASJ