The obliquity of HIP 67522 b: a 17 Myr old transiting hot Jupiter-sized planet

• Published in: arXiv.org
• Main Authors: Heitzmann, Alexis, Zhou, George, Quinn, Samuel N, Marsden, Stephen C, Wright, Duncan, Petit, Pascal, Vanderburg, Andrew M, Bouma, Luke G, Mann, Andrew W, Rizzuto, Aaron C
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 28.10.2021
• Subjects: Extrasolar planets; Gas giant planets; Physics - Earth and Planetary Astrophysics; Physics - Solar and Stellar Astrophysics; Planet formation; Planetary evolution; Surface brightness; Transit
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2109.04174

HIP 67522 b is a 17 Myr old, close-in (\(P_{orb} = 6.96\) d), Jupiter-sized (\(R = 10\,R_{\oplus}\)) transiting planet orbiting a Sun like star in the Sco-Cen OB association. We present our measurement of the system's projected orbital obliquity via two spectroscopic transit observations using the CHIRON spectroscopic facility. We present a global model that accounts for large surface brightness features typical of such young stars during spectroscopic transit observations. With a value of \(|\lambda| = 5.8^{+2.8\,\circ}_{-5.7}\), it is unlikely that this well-aligned system is the result of a high eccentricity driven migration history. By being the youngest planet with a known obliquity, HIP 67522 b holds a special place in contributing to our understanding of giant planet formation and evolution. Our analysis shows the feasibility of such measurements for young and very active stars.