Measurement of the Spin-Orbit Angle of Exoplanet HAT-P-1b

We present new spectroscopic and photometric observations of the HAT-P-1 planetary system. Spectra obtained during three transits exhibit the Rossiter-McLaughlin effect, allowing us to measure the angle between the sky projections of the stellar spin axis and orbit normal, \lambda = 3.7 +/- 2.1 degr...

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Bibliographic Details
Published in:arXiv.org 2008-06
Main Authors: Johnson, John A, Winn, Joshua N, Narita, Norio, Enya, Keigo, Williams, Peter K G, Marcy, Geoffrey W, Sato, Bun'ei, Ohta, Yasuhiro, Taruya, Atsushi, Suto, Yasushi, Turner, Edwin L, Bakos, Gaspar, Butler, R Paul, Vogt, Steven S, Aoki, Wako, Tamura, Motohide, Yamada, Toru, Yoshii, Yuzuru, Marton Hidas
Format: Article
Language:English
Subjects:
Eccentric orbits
Extrasolar planets
Light curve
Migration
Photometry
Planetary evolution
Planetary orbits
Planetary systems
Transit
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Summary:We present new spectroscopic and photometric observations of the HAT-P-1 planetary system. Spectra obtained during three transits exhibit the Rossiter-McLaughlin effect, allowing us to measure the angle between the sky projections of the stellar spin axis and orbit normal, \lambda = 3.7 +/- 2.1 degrees. The small value of \lambda for this and other systems suggests that the dominant planet migration mechanism preserves spin-orbit alignment. Using two new transit light curves, we refine the transit ephemeris and reduce the uncertainty in the orbital period by an order of magnitude. We find a upper limit on the orbital eccentricity of 0.067, with 99% confidence, by combining our new radial-velocity measurements with those obtained previously.
ISSN:2331-8422
DOI:10.48550/arxiv.0806.1734