Published online by Cambridge University Press: 01 June 2011
After the first transiting exoplanet was observed in 1999, other systems discovered from radial velocity surveys were also monitored to look for possible transits. Surveys from the ground and from space were quickly set up to carry out ‘blind searches’ for new planets from their periodic transit signatures alone.
Transiting planets are of particular importance because their light curves provide an estimate of their radii. Densities follow from their mass, which in turn gives a first estimate of their composition. Further probing of the planet's structural and atmospheric properties are accessible from photometry and spectroscopy during the transit, and during the secondary eclipse when the planet passes behind the star.
By the end of 2010, some 70 transiting planets were known, searches from ground and space were still intensifying, and new properties of the planetary population – both individual and statistical – were rapidly unfolding.
This chapter covers sequentially the search for transiting planets, their characterisation from their light curves, the search for reflected light, second-order effects on the light curves and transit times, and follow-up photometry and spectroscopy during the transit and secondary eclipse. A high proportion of transiting planets turn out to be close-in ‘hot Jupiters’, and a review of their general properties is also covered.
Given a suitable alignment geometry, light from the host star is attenuated by the transit of a planet across its disk, with the effect repeating at the orbital period.