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Judith Korth



TOI-2285b : A 1.7 Earth-radius planet near the habitable zone around a nearby M dwarf


  • Akihiko Fukui
  • Tadahiro Kimura
  • Teruyuki Hirano
  • Norio Narita
  • Takanori Kodama
  • Yasunori Hori
  • Masahiro Ikoma
  • Enric Pallé
  • Felipe Murgas
  • Hannu Parviainen
  • Kiyoe Kawauchi
  • Mayuko Mori
  • Emma Esparza-Borges
  • Allyson Bieryla
  • Jonathan Irwin
  • Boris S. Safonov
  • Keivan G. Stassun
  • Leticia Alvarez-Hernandez
  • Víctor J.S. Béjar
  • Núria Casasayas-Barris
  • Guo Chen
  • Nicolas Crouzet
  • Jerome P. De Leon
  • Keisuke Isogai
  • Taiki Kagetani
  • Peter Klagyivik
  • Judith Korth
  • Seiya Kurita
  • Nobuhiko Kusakabe
  • John Livingston
  • Rafael Luque
  • Alberto Madrigal-Aguado
  • Giuseppe Morello
  • Taku Nishiumi
  • Jaume Orell-Miquel
  • Mahmoudreza Oshagh
  • Manuel Śanchez-Benavente
  • Monika Stangret
  • Yuka Terada
  • Noriharu Watanabe
  • Yujie Zou
  • Motohide Tamura
  • Takashi Kurokawa
  • Masayuki Kuzuhara
  • Jun Nishikawa
  • Masashi Omiya
  • Sébastien Vievard
  • Akitoshi Ueda
  • David W. Latham
  • Samuel N. Quinn
  • Ivan S. Strakhov
  • Alexandr A. Belinski
  • Jon M. Jenkins
  • George R. Ricker
  • Sara Seager
  • Roland Vanderspek
  • Joshua N. Winn
  • David Charbonneau
  • David R. Ciardi
  • Karen A. Collins
  • John P. Doty
  • Etienne Bachelet
  • Daniel Harbeck

Summary, in English

We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 d. We identified the transit signal from the Transiting Exoplanet Survey Satellite photometric data, which we confirmed with ground-based photometric observations using the multiband imagers MuSCAT2 and MuSCAT3. Combining these data with other follow-up observations including high-resolution spectroscopy with the Tillinghast Reflector Echelle Spectrograph, high-resolution imaging with the SPeckle Polarimeter, and radial velocity (RV) measurements with the InfraRed Doppler instrument, we find that the planet has a radius of 1.74 ± 0.08, R⊕, a mass of < 19.5 M⊕ (95% c.l.), and an insolation flux of 1.54 ± 0.14 times that of the Earth. Although the planet resides just outside the habitable zone for a rocky planet, if the planet harbors an H2O layer under a hydrogen-rich atmosphere, then liquid water could exist on the surface of the H2O layer depending on the planetary mass and water mass fraction. The bright host star in the near-infrared (Ks = 9.0) makes this planet an excellent target for further RV and atmospheric observations to improve our understanding of the composition, formation, and habitability of sub-Neptune-sized planets.

Publishing year







Publications of the Astronomical Society of Japan





Document type

Journal article


Oxford University Press


  • planets and satellites: detection
  • planets and satellites: individual (TOI-2285b)
  • planets and satellites: interiors
  • techniques: photometric
  • techniques: radial velocities




  • ISSN: 0004-6264