Improved Measurement of the Rossiter-McLaughlin Effect in the Exoplanetary System HD 17156
Abstract
We present an improved measurement of the Rossiter-McLaughlin effect for the exoplanetary system HD 17156, based on radial-velocity data gathered with the Subaru 8.2-m telescope throughout the planetary transit of UT 2008 November 7. The data allow for a precise and independent determination of the projected spin-orbit angle of this system: λ = 10.0° ± 5.1°. This result supersedes the previous claim of λ = 62° ± 25° (2008, PASJ, 60, L1), which was based on lower-precision data with poor statistics. Thus the stellar spin and planetary orbital axes of the HD 17156 system are likely to be well-aligned, despite the planet's large orbital eccentricity suggesting a history of strong dynamical interactions.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- October 2009
- DOI:
- 10.1093/pasj/61.5.991
- arXiv:
- arXiv:0905.4727
- Bibcode:
- 2009PASJ...61..991N
- Keywords:
-
- stars: planetary systems: individual (HD 17156);
- stars: rotation;
- techniques: radial velocities;
- techniques: spectroscopic;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 16 pages, 3 figures, 3 tables, PASJ accepted