Jason W. Barnes et al. 2009 ApJ 706 877 doi:10.1088/0004-637X/706/1/877
Jason W. Barnes1, Curtis S. Cooper2,3, Adam P. Showman2 and William B. Hubbard2
Show affiliationsSeveral 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.
eclipses; planets and satellites: individual (HD189733b, HD209458b); techniques: photometric
Issue 1 (2009 November 20)
Received 2009 May 6, accepted for publication 2009 October 13
Published 2009 November 6
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S. Komossa and David Merritt 2008 ApJ 689 L89
Matthias Schmidt 2004 J. Phys.: Condens. Matter 16 L351
K. Coble et al. 2007 The Astronomical Journal 134 897
Eric F. Bell et al. 2004 ApJ 608 752
S Libonate and P Foukal 2000 Metrologia 37 369
T L Francis et al 2004 New J. Phys. 6 185
M. L. N. Ashby et al. 2009 ApJ 701 428
N. Z. Scoville et al. 1997 ApJ 484 702
Katharina Lodders 1999 ApJ 519 793