Binary star size, luminosity, and approximate shape) of both members of the system. While a number of binary star systems have been found to harbor extrasolar planets, such systems are comparatively rare compared to single star systems. Observations by the Kepler space telescope have shown that most single stars of the same type as the Sun have plenty of planets, but only one-third of binary stars do. According to theoretical simulations, even widely separated binary stars often disrupt the discs of rocky grains from which protoplanets form. On the other hand, other simulations suggest that the presence of a binary companion can
Kepler object of interest planet that is substantially larger than what is estimated by "Kepler". This occurs when there are sources of light other than simply the star being transited, such as in a binary system. In cases such as these, there is more surface area producing light than is assumed, so a given transit signal is larger than assumed. Since roughly 34% of stellar systems are binaries, up to 34% of KOI signals could be from planets within binary systems and, consequently, be larger than estimated (assuming planets are as likely to form in binary systems as they are in single star systems).