S21A0129

The origin of close-in giant planets (e.g., hot Jupiters) is the most enduring problem in exoplanetary science. A promising approach to solve this problem is to measure the angle of host star’s spin with respect to the planetary orbital axis (so-called “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 main-sequence (relatively old) stars, since until recently only a small number of transiting planets have been detected around very young stars (<1 Gyr), most of which are relatively small planets and not suitable for obliquity measurements. Here, we propose Subaru/IRD (or HDS) observations of a spectroscopic transit of HIP 67522b, which is currently the youngest hot Jupiter (age ≈ 17 Myr) discovered to date. Given that the timescale of tidal spin-orbit “realignment" for hot Jupiters is much longer than the age of the system, the system should preserve the primordial stellar obliquity before it is affected by subsequent dynamical processes. When combined with atmospheric characterizations, HIP 67522b would provide an invaluable testing bench on the formation and evolution processes of close-in giant planets.

This document was translated from L^AT_EX by H^EV^EA.