A prograde, low-inclination orbit for the very hot jupiter WASP-3b

Anjali Tripathi, Joshua N. Winn, John Asher Johnson, Andrew W. Howard, Sam Halverson, Geoffreyw Marcy, Matthew J. Holman, Katherine R. De Kleer, Joshua A. Carter, Gilbert A. Esquerdo, Marke Everett, Nicole E. Cabrera

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


We present new spectroscopic and photometric observations of the transiting exoplanetary system WASP-3. Spectra obtained during two separate transits exhibit the Rossiter-McLaughlin (RM) effect and allow us to estimate the sky-projected angle between the planetary orbital axis and the stellar rotation axis, λ = 3.3+2.5 -4.4deg. This alignment between the axes suggests that WASP-3b has a low orbital inclination relative to the equatorial plane of its parent star. During our first night of spectroscopic measurements, we observed an unexpected redshift briefly exceeding the expected sum of the orbital and RM velocities by 140ms-1. This anomaly could represent the occultation of material erupting from the stellar photosphere, although it is more likely to be an artifact caused by moonlight scattered into the spectrograph.

Original languageEnglish (US)
Pages (from-to)421-428
Number of pages8
JournalAstrophysical Journal
Issue number1
StatePublished - 2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Planetary systems
  • Stars: activity
  • Stars: individual (WASP-3)
  • Techniques: radial velocities


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