An Earth-sized Planet around an M5 Dwarf Star at 22 pc

Narita, Norio; Lam, Kristine W. F.; Kasagi, Yui; Grziwa, Sascha; Livingston, John H.; Dai, Fei; Hirano, Teruyuki; Ishikawa, Hiroyuki Tako; Miyakawa, Kohei; Serrano, Luisa M.; Matsumoto, Yuji; Kokubo, Eiichiro; Kimura, Tadahiro; Ikoma, Masahiro; Winn, Joshua N.; Wisniewski, John P.; Harakawa, Hiroki; Teng, Huan-Yu; Cochran, William D.; Fukui, Akihiko; Gandolfi, Davide; Guenther, Eike W.; Hori, Yasunori; Ikuta, Kai; Kawauchi, Kiyoe; Knudstrup, Emil; Korth, Judith; Kotani, Takayuki; Krishnamurthy, Vigneshwaran; Kudo, Tomoyuki; Kurokawa, Takashi; Kuzuhara, Masayuki; Luque, Rafael; Mori, Mayuko; Nishikawa, Jun; Omiya, Masashi; Orell-Miquel, Jaume; Palle, Enric; Persson, Carina M.; Redfield, Seth; Serabyn, Eugene; Smith, Alexis M. S.; Takahashi, Aoi; Takarada, Takuya; Ueda, Akitoshi; Van Eylen, Vincent; Vievard, Sébastien; Tamura, Motohide; Sato, Bun'ei
Bibliographical reference

The Astronomical Journal

Advertised on:
3
2023
Number of authors
49
IAC number of authors
4
Citations
1
Refereed citations
1
Description
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.
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Exoplanets and Astrobiology

The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable

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