S22A0058

Spectroscopic observations of a planetary transit offer a unique opportunity to probe the evolution history of close-in planets though the measurements of the stellar obliquity and transmission spectroscopy for exoplanet atmosphere. Those observations have almost exclusively been conducted for main-sequence stars, since until recently only a small number of transiting planets have been identified around very young stars (<100 Myr). Here, we propose re-observations of a spectroscopic transit of HIP 67522b, which is currently the youngest hot Jupiter (age ≈ 17 Myr) discovered to date. We observed a partial transit of HIP 67522b with IRD in 2021 April, and found tentative evidence that the system has a good spin-orbit alignment and the planet has an extended Helium atmosphere, but due to the lack of the first-half transit as well as the out-of-transit baseline data, we were unable to draw “robust" conclusions on the stellar obliquity and atmospheric excess absorption. Revisiting the system with another transit observation with IRD, we wish to make more robust measurements of the stellar obliquity and precisely constrain the atmospheric escape rate from this youngest hot Jupiter, which would provide invaluable clue to discuss the formation and dynamical history of close-in planets.

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