S20A0092abst
S20A0092
The origin of close-in giant planets is the most enduring problem in exoplanetary science. A promising approach to this problem is to measure the angle of host star’s spin with respect to the planetary orbital axis (“stellar obliquity"). This is because the various migration theories for close-in planets differ strongly in their predictions on the obliquity. Measurements of the stellar obliquity have been almost exclusively conducted for solar-type, main-sequence stars, and little is known on the obliquity for cool stars (M dwarfs) or young systems. To measure the obliquity for such unexplored systems, we propose a Subaru/IRD observation of the Rossiter-McLaughlin (RM) effect for a super-Neptune planet, K2-33b, orbiting a very young M3 dwarf in the Upper Scorpius OB Association (5−11 Myr). The planet formation and evolution around M dwarfs may be substantially different from those around solar-type stars, for their lower masses and fully convective envelopes. Given its extremely young age, K2-33 may preserve the primordial obliquity before it is disturbed by subsequent dynamical processes (e.g., star-planet tidal realignment). Our measurement will provide the very first sample on the obliquity for young, M dwarfs, and it will become an important milestone regardless of the result.
This document was translated from LATEX by HEVEA.