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.
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