An Earth-sized Planet around an M5 Dwarf Star at 22 pc
Journal article, 2023
We report on the discovery of an Earth-sized transiting planet (R p = 1.015 ± 0.051 R ⊕) in a P = 4.02 day orbit around K2-415 (EPIC 211414619), an M5V star at 22 pc. The planet candidate was first identified by analyzing the light-curve data obtained by the K2 mission, and it is here shown to exist in the most recent data from TESS. Combining the light curves with the data secured by our follow-up observations, including high-resolution imaging and near-infrared spectroscopy with IRD, we rule out false-positive scenarios, finding a low false-positive probability of 2 × 10−4. Based on IRD’s radial velocities of K2-415, which were sparsely taken over three years, we obtain a planet mass of 3.0 ± 2.7 M ⊕ (M p < 7.5 M ⊕ at 95% confidence) for K2-415b. Being one of the lowest-mass stars (≈0.16 M ⊙) known to host an Earth-sized transiting planet, K2-415 will be an interesting target for further follow-up observations, including additional radial velocity monitoring and transit spectroscopy.
Author
T. Hirano
The Graduate University for Advanced Studies (SOKENDAI)
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
Fei Dai
National Aeronautics and Space Administration (NASA)
California Institute of Technology (Caltech)
J. Livingston
National Astronomical Observatory of Japan
The Graduate University for Advanced Studies (SOKENDAI)
National Institutes of Natural Sciences
S. Grziwa
University of Cologne
K. W.F. Lam
German Aerospace Center (DLR)
Yui Kasagi
National Astronomical Observatory of Japan
The Graduate University for Advanced Studies (SOKENDAI)
N. Narita
National Institutes of Natural Sciences
Instituto de Astrofísica de Canarias
University of Tokyo
Hiroyuki Tako Ishikawa
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
Kohei Miyakawa
National Astronomical Observatory of Japan
L. M. Serrano
University of Turin
Yuji Matsumoto
National Astronomical Observatory of Japan
Eiichiro Kokubo
National Astronomical Observatory of Japan
Tadahiro Kimura
University of Tokyo
Masahiro Ikoma
National Astronomical Observatory of Japan
University of Tokyo
J. N. Winn
Princeton University
John P. Wisniewski
George Mason University
Hiroki Harakawa
National Astronomical Observatory of Japan
Huan Yu Teng
Tokyo Institute of Technology
W. D. Cochran
University of Texas
A. Fukui
Instituto de Astrofísica de Canarias
University of Tokyo
D. Gandolfi
University of Turin
Eike W. Guenther
Thüringer Landessternwarte Tautenburg
Yasunori Hori
The Graduate University for Advanced Studies (SOKENDAI)
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
Kai Ikuta
University of Tokyo
Kiyoe Kawauchi
University of Tokyo
E. Knudstrup
Aarhus University
Judith Korth
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Takayuki Kotani
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
The Graduate University for Advanced Studies (SOKENDAI)
Vigneshwaran Krishnamurthy
National Institutes of Natural Sciences
National Astronomical Observatory of Japan
Tomoyuki Kudo
National Astronomical Observatory of Japan
Takashi Kurokawa
National Institutes of Natural Sciences
Tokyo University of Agriculture and Technology
M. Kuzuhara
National Institutes of Natural Sciences
National Astronomical Observatory of Japan
R. Luque
University of Chicago
Mayuko Mori
University of Tokyo
Jun Nishikawa
National Institutes of Natural Sciences
The Graduate University for Advanced Studies (SOKENDAI)
National Astronomical Observatory of Japan
Masashi Omiya
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
J. Orell-Miquel
Instituto de Astrofísica de Canarias
University of La Laguna
E. Palle
University of La Laguna
Instituto de Astrofísica de Canarias
Carina Persson
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
S. Redfield
Wesleyan University
E. Serabyn
California Institute of Technology (Caltech)
Alexis M.S. Smith
German Aerospace Center (DLR)
Aoi Takahashi
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
Takuya Takarada
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
Akitoshi Ueda
National Astronomical Observatory of Japan
Vincent Van Eylen
University College London (UCL)
Sébastien Vievard
National Institutes of Natural Sciences
National Astronomical Observatory of Japan
Motohide Tamura
National Institutes of Natural Sciences
National Astronomical Observatory of Japan
University of Tokyo
Bun’ei Sato
Tokyo Institute of Technology
Astronomical Journal
0004-6256 (ISSN) 1538-3881 (eISSN)
Vol. 165 3 131Subject Categories (SSIF 2011)
Subatomic Physics
Astronomy, Astrophysics and Cosmology
Geophysics
DOI
10.3847/1538-3881/acb7e1