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

Research output: Contribution to journalArticle

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.

Details

Authors
  • Megan Bedell
  • Jacob L. Bean
  • Jorge Meléndez
  • Sean M. Mills
  • Daniel C. Fabrycky
  • Fabrício C. Freitas
  • Ivan Ramírez
  • Martin Asplund
  • Fan Liu
  • David Yong
Organisations
External organisations
  • University of Chicago
  • Australian National University
  • University of São Paulo
  • University of Texas
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology

Keywords

  • planets and satellites: fundamental parameters, stars: abundances, stars: fundamental parameters, techniques: spectroscopic
Original languageEnglish
Article number94
JournalAstrophysical Journal
Volume839
Issue number2
Publication statusPublished - 2017 Apr 20
Publication categoryResearch
Peer-reviewedYes