arXiv 0804.22592008-04-14astro-ph

The Prograde Orbit of Exoplanet TrES-2b

Joshua N. Winn, John Asher Johnson, Norio Narita, Yasushi Suto, Edwin L. Turner, Debra A. Fischer, R. Paul Butler, Steven S. Vogt, Francis T. O'Donovan, B. Scott Gaudi

备注：: ApJ, in press [15 pages]
DOI：: 10.1086/589235

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We monitored the Doppler shift of the G0V star TrES-2 throughout a transit of its giant planet. The anomalous Doppler shift due to stellar rotation (the Rossiter-McLaughlin effect) is discernible in the data, with a signal-to-noise ratio of 2.9, even though the star is a slow rotator. By modeling this effect we find that the planet's trajectory across the face of the star is tilted by -9 +/- 12 degrees relative to the projected stellar equator. With 98% confidence, the orbit is prograde.

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