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

doi:10.3847/0004-6256/152/6/165

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arXiv · 1608.03627

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

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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. 2016-08-11. 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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