Protostars and Planets VI, Heidelberg, July 15-20, 2013
The curiously circular orbit of Kepler-16b
Dunhill, Alex (University of Leicester)
Alexander, Richard (University of Leicester)
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). We will present high-resolution 3D smoothed-particle hydrodynamics simulations of a Kepler-16 analogue embedded in a circumbinary disc, and show that the planetís eccentricity is damped by its interaction with the protoplanetary disc. Using this, we 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. We argue that this has implications for the route that planet formation takes in the circumbinary environment, as secular evolution of circumbinary discs implies that these planets likely 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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