Spin-Orbit Alignment of the TrES-4 Transiting Planetary System and Possible Additional Radial-Velocity Variation
Author(s)
Narita, Norio
Sato, Bunei
Hirano, Teruyuki
Winn, Joshua Nathan
Aoki, Wako
Tamura, Motohide
Date Issued
June 2010
Journal
Publications of the Astronomical Society of Japan
Publisher
Astronomical Society of Japan
Citation
Narita, Norio, et al. "Spin-Orbit Alignment of the Tres-4 Transiting Planetary System and Possible Additional Radial-Velocity Variation." Publications of the Astronomical Society of Japan 62 3 (2010): 653-60.
Version
Author's final manuscript
Abstract
We report new radial velocities of the TrES-4 transiting planetary system, including observations of
a full transit, with the High Dispersion Spectrograph of the Subaru 8.2m telescope. Modeling of the
Rossiter-McLaughlin effect indicates that TrES-4b has closely aligned orbital and stellar spin axes, with [lambda]=6.3[degrees]±4.7[degrees]. The close spin-orbit alignment angle of TrES-4b seems to argue against a migration history
involving planet-planet scattering or Kozai cycles, although there are two nearby faint stars that could be binary companion candidates. Comparison of our out-of-transit data from 4 different runs suggest that the star exhibits radial velocity variability of 20 m s[superscript −1] in excess of a single Keplerian orbit. Although the cause of the excess radial velocity variability is unknown, we discuss various possibilities including systematic measurement errors, starspots or other intrinsic motions, and additional companions besides the transiting planet.
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
http://pasj.asj.or.jp/v62/n3/620311/620311a.html
