The Obliquity of HIP 67522 b: A 17 Myr Old Transiting Hot, Jupiter-sized Planet
A. Heitzmann, George Zhou, Samuel N. Quinn, S. C. Marsden, D. J. Wright, P. Petit, Andrew Vanderburg, Luke G. Bouma, Andrew W. Mann, Aaron C. Rizzuto
Abstract
Abstract HIP 67522 b is a 17 Myr old, close-in ( P orb = 6.96 days), Jupiter-sized ( R = 10 R ⊕ ) 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo stretchy="false">∣</mml:mo> <mml:mi>λ</mml:mi> <mml:mo stretchy="false">∣</mml:mo> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>5.8</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>5.7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2.8</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>°</mml:mo> </mml:math> 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.