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Judith Korth



K2-155 : A Bright Metal-poor M Dwarf with Three Transiting Super-Earths


  • Teruyuki Hirano
  • Fei Dai
  • John H. Livingston
  • Yuka Fujii
  • William D. Cochran
  • Michael Endl
  • Davide Gandolfi
  • Seth Redfield
  • Joshua N. Winn
  • Eike W. Guenther
  • Jorge Prieto-Arranz
  • Simon Albrecht
  • Oscar Barragan
  • Juan Cabrera
  • P. Wilson Cauley
  • Szilard Csizmadia
  • Hans Deeg
  • Philipp Eigmüller
  • Anders Erikson
  • Malcolm Fridlund
  • Akihiko Fukui
  • Sascha Grziwa
  • Artie P. Hatzes
  • Judith Korth
  • Norio Narita
  • David Nespral
  • Prajwal Niraula
  • Grzegorz Nowak
  • Martin Pätzold
  • Enric Palle
  • Carina M. Persson
  • Heike Rauer
  • Ignasi Ribas
  • Alexis M.S. Smith
  • Vincent Van Eylen

Summary, in English

We report on the discovery of three transiting super-Earths around K2-155 (EPIC 210897587), a relatively bright early M dwarf (V = 12.81 mag) observed during Campaign 13 of the NASA K2 mission. To characterize the system and validate the planet candidates, we conducted speckle imaging and high-dispersion optical spectroscopy, including radial velocity measurements. Based on the K2 light curve and the spectroscopic characterization of the host star, the planet sizes and orbital periods are 1.55-0.17+0.20R and 6.34365 ±0.00028 days for the inner planet; 1.95-0.22+0.27R and 13.85402 ±0.00088 days for the middle planet; and 1.64-0.17+0.18 R and 40.6835 ±0.0031 days for the outer planet. The outer planet (K2-155d) is near the habitable zone, with an insolation 1.67 ±0.38 times that of the Earth. The planet's radius falls within the range between that of smaller rocky planets and larger gas-rich planets. To assess the habitability of this planet, we present a series of three-dimensional global climate simulations, assuming that K2-155d is tidally locked and has an Earth-like composition and atmosphere. We find that the planet can maintain a moderate surface temperature if the insolation proves to be smaller than ∼1.5 times that of the Earth. Doppler mass measurements, transit spectroscopy, and other follow-up observations should be rewarding, as K2-155 is one of the optically brightest M dwarfs known to harbor transiting planets.

Publishing year





Astronomical Journal





Document type

Journal article


IOP Publishing


  • planets and satellites: detection
  • stars: individual (K2-155 = EPIC 210897587)
  • techniques: photometric
  • techniques: radial velocities
  • techniques: spectroscopic




  • ISSN: 0004-6256