Detecting the wind-driven shapes of extrasolar giant planets from transit photometry

Jason W. Barnes, Curtis S. Cooper, Adam P. Showman, William B. Hubbard

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Several processes can cause the shape of an extrasolar giant planet's shadow, as viewed in transit, to depart from circular. In addition to rotational effects, cloud formation, non-homogenous haze production and movement, and dynamical effects (winds) could also be important. When such a planet transits its host star as seen from the Earth, the asphericity will introduce a deviation in the transit light curve relative to the transit of a perfectly spherical (or perfectly oblate) planet. We develop a theoretical framework to interpret planetary shapes. We then generate predictions for transiting planet shapes based on a published theoretical dynamical model of HD189733b. Using these shape models we show that planet shapes are unlikely to introduce detectable light-curve deviations (those >1 × 10-5 of the host star), but that the shapes may lead to astrophysical sources of systematic error when measuring planetary oblateness, transit time, and impact parameter.

Original languageEnglish (US)
Pages (from-to)877-884
Number of pages8
JournalAstrophysical Journal
Issue number1
StatePublished - 2009


  • Eclipses
  • Planets and satellites: Individual (HD189733b, HD209458b)
  • Techniques: Photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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