Institute of Astronomy

The curiously circular orbit of Kepler-16b

SpeakerTalk DateTalk Series
Alex Dunhill28 July 2014Across HR 2014 Posters


The discovery of a number of circumbinary planets lends a new tool to astrophysicists seeking to understand how and where planet formation takes place. Of the increasingly numerous circumbinary systems, Kepler-16 is arguably the most dynamically interesting: it consists of a planet on an almost perfectly circular orbit (e = 0.0069) around a moderately eccentric binary (e = 0.16). I will present high-resolution 3D smoothed-particle hydrodynamics simulations of a Kepler-16 analogue embedded in a circumbinary disc, and show that the planet's eccentricity is damped by its interaction with the protoplanetary disc. Using this, one can place a lower limit on the gas surface density in the real disc through which Kepler-16b migrated. This suggests that Kepler-16b, and other circumbinary planets, formed and migrated in relatively massive discs. I argue that the has strong implications for the route that planet formation takes in the circumbinary environment, as secular evolution of circumbinary discs requires that thes e planets formed early on in the lifetime of the disc and migrated inwards before the disc lost a significant amount of its original mass.


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