The Aligned Orbit of WASP-148b, the Only Known Hot Jupiter with a Nearby Warm Jupiter Companion, from NEID and HIRES

• Published in: arXiv.org 2022-02
• Main Authors: Xian-Yu, Wang, Rice, Malena, Wang, Songhu, Bonan Pu, Stefánsson, Guðmundur, Mahadevan, Suvrath, Radzom, Brandon, Giacalone, Steven, Zhen-Yu, Wu, Esposito, Thomas M, Dalba, Paul A, Avsar, Arin, Holden, Bradford, Skiff, Brian, Polakis, Tom, Voeller, Kevin, Logsdon, Sarah E, Klusmeyer, Jessica, Schweiker, Heidi, Dong-Hong, Wu, Beard, Corey, Dai, Fei, Lubin, Jack, Weiss, Lauren M, Bender, Chad F, Blake, Cullen H, Dressing, Courtney D, Halverson, Samuel, Hearty, Fred, Howard, Andrew W, Huber, Daniel, Isaacson, Howard, Jackman, James A G, Llama, Joe, McElwain, Michael W, Rajagopal, Jayadev, Roy, Arpita, Robertson, Paul, Schwab, Christian, Shkolnik, Evgenya L, Wright, Jason, Laughlin, Gregory
• Format: Article
• Language: English
• Subjects: Alignment; Cool stars; Deposition; Extrasolar planets; Gas giant planets; Hot stars; Jupiter; Planetary systems; Solar system
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2110.08832

We present spectroscopic measurements of the Rossiter-McLaughlin effect for WASP-148b, the only known hot Jupiter with a nearby warm-Jupiter companion, from the WIYN/NEID and Keck/HIRES instruments. This is one of the first scientific results reported from the newly commissioned NEID spectrograph, as well as the second obliquity constraint for a hot Jupiter system with a close-in companion, after WASP-47. WASP-148b is consistent with being in alignment with the sky-projected spin axis of the host star, with \(\lambda=-8^{\circ}.2^{{+8^{\circ}.7}}_{-9^{\circ}.7}\). The low obliquity observed in the WASP-148 system is consistent with the orderly-alignment configuration of most compact multi-planet systems around cool stars with obliquity constraints, including our solar system, and may point to an early history for these well-organized systems in which migration and accretion occurred in isolation, with relatively little disturbance. By contrast, previous results have indicated that high-mass and hot stars appear to more commonly host a wide range of misaligned planets: not only single hot Jupiters, but also compact systems with multiple super-Earths. We suggest that, to account for the high rate of spin-orbit misalignments in both compact multi-planet and isolated-hot-Jupiter systems orbiting high-mass and hot stars, spin-orbit misalignments may be caused by distant giant planet perturbers, which are most common around these stellar types.