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

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


We monitored the Doppler shift of the G0 V 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° relative to the projected stellar equator. With 98% confidence, the orbit is prograde.

Original languageEnglish (US)
Pages (from-to)1283-1288
Number of pages6
JournalAstrophysical Journal
Issue number2
StatePublished - Aug 1 2008

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Planetary systems
  • Planetary systems: Formation
  • Stars: Individual (GSC 03549-02811, TrES-2)
  • Stars: Rotation


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