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arXiv · 1608.03627

The Orbit and Mass of the Third Planet in the Kepler-56 System

Oderah Justin Otor·Benjamin T. Montet·John Asher Johnson·David Charbonneau·Andrew Collier-Cameron·Andrew W. Howard·Howard Isaacson·David W. Latham·Mercedes Lopez-Morales·Christophe Lovis·Michel Mayor·Giusi Micela·Emilio Molinari·Francesco Pepe·Giampaolo Piotto·David F. Phillips·Didier Queloz·Ken Rice·Dimitar Sasselov·Damien Ségransan·Alessandro Sozzetti·Stéphane Udry·Chris Watson
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Abstract

While the vast majority of multiple-planet systems have their orbital angular momentum axes aligned with the spin axis of their host star, Kepler-56 is an exception: its two transiting planets are coplanar yet misaligned by at least 40 degrees with respect to their host star. Additional follow-up observations of Kepler-56 suggest the presence of a massive, non-transiting companion that may help explain this misalignment. We model the transit data along with Keck/HIRES and HARPS-N radial velocity data to update the masses of the two transiting planets and infer the physical properties of the third, non-transiting planet. We employ a Markov Chain Monte Carlo sampler to calculate the best-fitting orbital parameters and their uncertainties for each planet. We find the outer planet has a period of 1002 $\pm$ 5 days and minimum mass of 5.61 $\pm$ 0.38 Jupiter masses. We also place a 95% upper limit of 0.80 m/s/yr on long-term trends caused by additional, more distant companions.

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Oderah Justin Otor, Benjamin T. Montet, John Asher Johnson, David Charbonneau, Andrew Collier-Cameron, Andrew W. Howard, Howard Isaacson, David W. Latham, Mercedes Lopez-Morales, Christophe Lovis, Michel Mayor, Giusi Micela, Emilio Molinari, Francesco Pepe, Giampaolo Piotto, David F. Phillips, Didier Queloz, Ken Rice, Dimitar Sasselov, Damien Ségransan, Alessandro Sozzetti, Stéphane Udry, Chris Watson. 2016-09-22. The Orbit and Mass of the Third Planet in the Kepler-56 System. https://doi.org/10.3847/0004-6256%2F152%2F6%2F165

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