ES-04-0004

Orbital architectures of triple-star systems that host transiting planets

Elise Evans, Trent Dupuy, Kendall Sullivan, Adam Kraus, Dan Huber

While often overlooked in exoplanet surveys, binary stars and higher order multiple star systems provide opportunities to study the environments in which any orbiting planets formed. This is under the assumption that the planet formed after the star system and therefore the stellar orbits that sculpted the formation environment are the same orbits observed today. Using our long-term Keck adaptive optics monitoring programme, we have measured astrometric orbit arcs of Kepler planet hosts that possess at least one stellar companion at projected separations of 20?200 AU. This work focuses on the 10 triple-star systems within our volume-limited survey. While planet hosting binary stars have two orbital planes to consider (the plane of the planet and the plane of the stellar binary), triple systems have an additional orbital plane from the third stellar companion. Orbital arcs allow the alignment of the system to be tested in order to determine if either of the stellar orbital planes are edge-on and therefore align with the edge-on orbit of the transiting planet. Complete orbital analysis of the triple star systems will enable us to establish whether specific orbital characteristics, such as eccentricity, create more favourable environments for planet formation within multiple star systems.