Kepler-11 is a Solar Twin: Revising the Masses and Radii of Benchmark Planets Via Precise Stellar Characterization

Megan Bedell; Jacob L. Bean; Jorge Melendez; Sean M. Mills; Daniel C. Fabrycky; Fabricio C. Freitas; Ivan Ramirez; Martin Asplund; Fan Liu; David Yong

doi:10.3847/1538-4357/aa6a1d

arXiv · 1611.06239

Kepler-11 is a Solar Twin: Revising the Masses and Radii of Benchmark Planets Via Precise Stellar Characterization

Megan Bedell·Jacob L. Bean·Jorge Melendez·Sean M. Mills·Daniel C. Fabrycky·Fabricio C. Freitas·Ivan Ramirez·Martin Asplund·Fan Liu·David Yong

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Abstract

The six planets of the Kepler-11 system are the archetypal example of a population of surprisingly low-density transiting planets revealed by the Kepler mission. We have determined the fundamental parameters and chemical composition of the Kepler-11 host star to unprecedented precision using an extremely high quality spectrum from Keck-HIRES (R$\simeq$67,000, S/N per pixel$\simeq$260 at 600 nm). Contrary to previously published results, our spectroscopic constraints indicate that Kepler-11 is a young main-sequence solar twin. The revised stellar parameters and new analysis raise the densities of the Kepler-11 planets by between 20-95% per planet, making them more typical of the emerging class of "puffy" close-in exoplanets. We obtain photospheric abundances of 22 elements and find that Kepler-11 has an abundance pattern similar to that of the Sun with a slightly higher overall metallicity. We additionally analyze the Kepler lightcurves using a photodynamical model and discuss the tension between spectroscopic and transit/TTV-based stellar density estimates.

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Megan Bedell, Jacob L. Bean, Jorge Melendez, Sean M. Mills, Daniel C. Fabrycky, Fabricio C. Freitas, Ivan Ramirez, Martin Asplund, Fan Liu, David Yong. 2016-11-18. Kepler-11 is a Solar Twin: Revising the Masses and Radii of Benchmark Planets Via Precise Stellar Characterization. https://doi.org/10.3847/1538-4357/aa6a1d

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