Confirmation of a Retrograde Orbit for Exoplanet Wasp-17b
Author(s)
Bayliss, Daniel D. R.
Winn, Joshua Nathan
Mardling, Rosemary A.
Sackett, Penny D.
Date Issued
October 2010
Journal
Astrophysical Journal Letters
Publisher
Institute of Physics
Citation
Bayliss, Daniel D. R. et al. "Confirmation of a Retrograde Orbit for Exoplanet Wasp-17b." 2010 ApJ 722.2 L224-L227
Version
Author's final manuscript
Abstract
We present high-precision radial velocity observations of WASP-17 throughout the transit of its close-in giant planet, using the MIKE spectrograph on the 6.5 m Magellan Telescope at Las Campanas Observatory. By modeling the Rossiter-McLaughlin effect, we find the sky-projected spin-orbit angle to be [lambda] = 167.4 ± 11.2 deg. This independently confirms the previous finding that WASP-17b is on a retrograde orbit, suggesting it underwent migration via a mechanism other than just the gravitational interaction between the planet and the disk. Interestingly, our result for [lambda] differs by 45 ± 13 deg from the previously announced value, and we also find that the spectroscopic transit occurs 15 ± 5 minutes earlier than expected, based on the published ephemeris. The discrepancy in the ephemeris highlights the need for contemporaneous spectroscopic and photometric transit observations whenever possible.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike 3.0
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/2041-8205/722/2/l224
