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korth

Judith Korth

Postdoc

korth

Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf

Author

  • K. Kawauchi
  • F. Murgas
  • E. Palle
  • N. Narita
  • A. Fukui
  • T. Hirano
  • H. Parviainen
  • H. T. Ishikawa
  • N. Watanabe
  • E. Esparaza-Borges
  • M. Kuzuhara
  • J. Orell-Miquel
  • V. Krishnamurthy
  • M. Mori
  • T. Kagetani
  • Y. Zou
  • K. Isogai
  • J. H. Livingston
  • S. B. Howell
  • N. Crouzet
  • J. P. de Leon
  • T. Kimura
  • T. Kodama
  • J. Korth
  • S. Kurita
  • A. Laza-Ramos
  • R. Luque
  • A. Madrigal-Aguado
  • K. Miyakawa
  • G. Morello
  • T. Nishiumi
  • G. E. F. Rodríguez
  • M. Sánchez-Benavente
  • M. Stangret
  • H. Teng
  • Y. Terada
  • C. L. Gnilka
  • N. Guerrero
  • H. Harakawa
  • K. Hodapp
  • Y. Hori
  • M. Ikoma
  • S. Jacobson
  • M. Konishi
  • T. Kotani
  • T. Kudo
  • T. Kurokowa
  • N. Kusakabe
  • J. Nishikawa
  • M. Omiya
  • T. Serizawa
  • M Tamura
  • A. Ueda
  • S. Vievard
Show all

Summary, in English

Context. The NASA space telescope TESS is currently in the
extended mission of its all-sky search for new transiting planets. Of
the thousands of candidates that TESS is expected to deliver, transiting
planets orbiting nearby M dwarfs are particularly interesting targets
since they provide a great opportunity to characterize their atmospheres
by transmission spectroscopy.


Aims. We aim to validate and characterize the new sub-Neptune-sized planet candidate TOI-2136.01 orbiting a nearby M dwarf (d = 33.36 ± 0.02pc, Teff = 3373 ± 108 K) with an orbital period of 7.852 days.


Methods. We use TESS data, ground-based multicolor photometry,
and radial velocity measurements with the InfraRed Doppler (IRD)
instrument on the Subaru Telescope to validate the planetary nature of
TOI-2136.01, and estimate the stellar and planetary parameters. We also
conduct high-resolution transmission spectroscopy to search for helium
in its atmosphere.


Results. We confirm that TOI-2136.01 (now named TOI-2136b) is a bona fide planet with a planetary radius of Rp = 2.20 ± 0.07R⊕ and a mass of Mp = 4.7−2.6+3.1 M⊕.
We also search for helium 10830 Å absorption lines and place an upper
limit on the equivalent width of <7.8 mÅ and on the absorption signal
of <1.44% with 95% confidence.


Conclusions. TOI-2136b is a sub-Neptune transiting a nearby and bright star (J = 10.8 mag), and is a potentially hycean planet, which is a new class of habitable planets with large oceans under a H2-rich
atmosphere, making it an excellent target for atmospheric studies to
understand the formation, evolution, and habitability of the small
planets.

Publishing year

2022-10-01

Language

English

Publication/Series

Astronomy and Astrophysics

Volume

666

Document type

Journal article

Publisher

EDP Sciences

Keywords

  • Planets and satellites: atmospheres
  • Planets and satellites: detection
  • Planets and satellites: individual: TOI-2136b
  • techniques: photometric
  • Techniques: radial velocities

Status

Published

ISBN/ISSN/Other

  • ISSN: 0004-6361