The Detection and Characterization of a Nontransiting Planet by Transit Timing Variations

Abstract

Unseen Planet The orbits of planetary bodies can be affected by gravitational interactions with other planets in the same system. If the planets can be seen to pass in front of their star (or to transit), the gravitational perturbations translate into variations in transit duration. Nesvorný et al. (p. 1133 , published online 10 May; see the Perspective by Murray ) inferred the presence of a far distant, previously unknown planet from the transit timing variations of a planet previously detected by the Kepler space telescope. The new planet is in a 57-day orbit and does not transit its host star. The analysis also revealed a third possible planet with a mass 1.7 times that of the Earth in a 6.8-day orbit. The radially spaced, roughly coplanar, and nearly circular orbits of the two confirmed planets mirror planetary orbits in our own solar system.