Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, and d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits

  title={Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, and d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits},
  author={Molly R. Kosiarek and Ian J. M. Crossfield and Kevin K. Hardegree-Ullman and John H. Livingston and Bj{\"o}rn Benneke and Gregory W. Henry and Ward S. Howard and David A. Berardo and Sarah C. Blunt and Benjamin J. Fulton and Lea A. Hirsch and Andrew W. Howard and Howard T. Isaacson and Erik A. Petigura and Evan Sinukoff and Lauren M. Weiss and Xavier Bonfils and Courtney D. Dressing and Heather A. Knutson and Joshua E. Schlieder and Michael W. Werner and Varoujan Gorjian and Jessica E. Krick and Farisa Y. Morales and Nicola Astudillo-Defru and J. M. Almenara and Xavier Delfosse and Thierry Forveille and Christophe Lovis and Michel Mayor and Felipe Murgas and Francesco A. Pepe and Nuno C. Santos and St{\'e}phane Udry and Hank Corbett and Octavi Fors and Nicholas M. Law and Jeffrey K. Ratzloff and Daniel del Ser},
  journal={The Astronomical Journal},
We report improved masses, radii, and densities for four planets in two bright M-dwarf systems, K2-3 and GJ3470, derived from a combination of new radial velocity and transit observations. Supplementing K2 photometry with follow-up Spitzer transit observations refined the transit ephemerides of K2-3 b, c, and d by over a factor of 10. We analyze ground-based photometry from the Evryscope and Fairborn Observatory to determine the characteristic stellar activity timescales for our Gaussian… Expand
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