Improved measurement of the Rossiter-McLaughlin effect in the exoplanetary system HD 17156

Norio Narita, Teruyuki Hirano, Bun'ei Sato, Joshua N. Winn, Yasushi Suto, Edwin L. Turner, Wako Aoki, Motohide Tamura, Toru Yamada

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36 Scopus citations


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° by Narita et al. (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.

Original languageEnglish (US)
Pages (from-to)991-997
Number of pages7
JournalPublications of the Astronomical Society of Japan
Issue number5
StatePublished - 2009

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Stars: planetary systems: individual (HD 17156)
  • Stars: rotation - techniques: radial velocities
  • Techniques: spectroscopic


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