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
(Submitted on 18 Nov 2016)

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?67,000, S/N per pixel?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 raise the densities of the Kepler-11 planets by about 30%, 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.

Comments: 14 pages, 7 figures; submitted to AAS journals
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:1611.06239 [astro-ph.EP]
(or arXiv:1611.06239v1 [astro-ph.EP] for this version)
Submission history
From: Megan Bedell
[v1] Fri, 18 Nov 2016 21:01:01 GMT (396kb,D)
https://arxiv.org/abs/1611.06239