Kepler-11 is a Solar Twin: Revising the Masses and Radii of Benchmark Planets via Precise Stellar Characterization
Date
2017
Authors
Bedell, Megan
Bean, Jacob
Meléndez, J
Mills, Sean M
Fabrycky, Daniel C
Freitas, Fabrıcio C.
Ramírez, I
Asplund, Martin
Liu, Fan
Yong, David
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Volume Title
Publisher
IOP Publishing
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 ≃ 67,000, S/N per pixel 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% and 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 light curves using a photodynamical model and discuss the tension between spectroscopic and transit/TTV-based estimates of stellar density.
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Keywords
planets and satellites: fundamental parameters, stars: abundances, stars: fundamental parameters, techniques: spectroscopic
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Source
The Astrophysical Journal
Type
Journal article
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Open Access
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