A high stellar obliquity in the WASP-7 exoplanetary system
Author(s)
Albrecht, Simon H.
Winn, Joshua Nathan
Butler, R. Paul
Crane, Jeffrey D.
Shectman, Stephen A.
Thompso, Ian B.
Hirano, Teruyuki
Wittenmyer, Robert A.
Date Issued
December 2011
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Albrecht, Simon et al. “A high stellar obliquity in the WASP-7 exoplanetary system.” The Astrophysical Journal 744.2 (2012): 189.
Version
Author's final manuscript
Abstract
We measure a tilt of 86° ± 6° between the sky projections of the rotation axis of the WASP-7 star and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise ("stellar jitter") with an amplitude of ≈30 m s–1 over a timescale of days.
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/10.1088/0004-637x/744/2/189
