The Aligned Orbit of the Eccentric Warm Jupiter K2-232b

Journal Article · Sun Aug 01 04:00:00 EDT 2021 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AC0626· OSTI ID:23159301

Wang, Songhu ^[1]; Winn, Joshua N. ^[2]; Addison, Brett C. ^[3]; Dai, Fei ^[4]; Rice, Malena; Laughlin, Gregory ^[5]; Holden, Bradford; Vogt, Steven S. ^[6]; Burt, Jennifer A. ^[7]; Wang, Xian-Yu ^[8]

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1. Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States)
2. Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States)
3. University of Southern Queensland, Centre for Astrophysics, West Street, Toowoomba, QLD 4350 Australia (Australia)
4. Division of Geological and Planetary Sciences 1200 E California Boulevard, Pasadena, CA 91125 (United States)
5. Department of Astronomy, Yale University, New Haven, CT 06511 (United States)
6. UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)
7. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
8. National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

Measuring the obliquity distribution of stars hosting warm Jupiters may help us to understand the formation of close-orbiting gas giants. Few such measurements have been performed due to practical difficulties in scheduling observations of the relatively infrequent and long-duration transits of warm Jupiters. Here, we report a measurement of the Rossiter–McLaughlin effect for K2-232 b, a warm Jupiter on an 11.17 day orbit with an eccentricity of 0.26. The data were obtained with the Automated Planet Finder during two separate transits. The planet’s orbit appears to be well aligned with the spin axis of the host star, with a projected spin–orbit angle of λ = −11.°1 ± 6.°6. Combined with the other available data, we find that high obliquities are almost exclusively associated with planets that either have an orbital separation greater than 10 stellar radii or orbit stars with effective temperatures hotter than 6000 K. This pattern suggests that the obliquities of the closest-orbiting giant planets around cooler stars have been damped by tidal effects.

• OSTI ID: 23159301
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 2 Vol. 162; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
HEAT EXCHANGERS
JUPITER PLANET
ORBITS
SPIN
STARS