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

DOI: 
10.1093/pasj/psab106
Publication date: 
08/02/2022
Main author: 
Fukui, Akihiko
IAA authors: 
Luque, Rafael
Authors: 
Fukui, Akihiko;Kimura, Tadahiro;Hirano, Teruyuki;Narita, Norio;Kodama, Takanori;Hori, Yasunori;Ikoma, Masahiro;Pallé, Enric;Murgas, Felipe;Parviainen, Hannu;Kawauchi, Kiyoe;Mori, Mayuko;Esparza-Borges, Emma;Bieryla, Allyson;Irwin, Jonathan;Safonov, Boris S.;Stassun, Keivan G.;Alvarez-Hernandez, Leticia;Béjar, Víctor J. S.;Casasayas-Barris, Núria;Chen, Guo;Crouzet, Nicolas;de Leon, Jerome P.;Isogai, Keisuke;Kagetani, Taiki;Klagyivik, Peter;Korth, Judith;Kurita, Seiya;Kusakabe, Nobuhiko;Livingston, John;Luque, Rafael;Madrigal-Aguado, Alberto;Morello, Giuseppe;Nishiumi, Taku;Orell-Miquel, Jaume;Oshagh, Mahmoudreza;Sánchez-Benavente, Manuel;Stangret, Monika;Terada, Yuka;Watanabe, Noriharu;Zou, Yujie;Tamura, Motohide;Kurokawa, Takashi;Kuzuhara, Masayuki;Nishikawa, Jun;Omiya, Masashi;Vievard, Sébastien;Ueda, Akitoshi;Latham, David W.;Quinn, Samuel N.;Strakhov, Ivan S.;Belinski, Alexandr A.;Jenkins, Jon M.;Ricker, George R.;Seager, Sara;Vanderspek, Roland;Winn, Joshua N.;Charbonneau, David;Ciardi, David R.;Collins, Karen A.;Doty, John P.;Bachelet, Etienne;Harbeck, Daniel
Journal: 
Publications of the Astronomical Society of Japan
Publication type: 
Article
Volume: 
74
Pages: 
L1-L8
Abstract: 
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 $1.74 \pm 0.08\, R_\oplus$, a mass of $\lt \!\!19.5\,M_\oplus$ ($95\%$ 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 H<SUB>2</SUB>O layer under a hydrogen-rich atmosphere, then liquid water could exist on the surface of the H<SUB>2</SUB>O layer depending on the planetary mass and water mass fraction. The bright host star in the near-infrared (K<SUB>s</SUB> = 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.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2022PASJ...74L...1F/abstract
ADS Bibcode: 
2022PASJ...74L...1F
Keywords: 
planets and satellites: detection;planets and satellites: individual (TOI-2285b);planets and satellites: interiors;techniques: photometric;techniques: radial velocities;Astrophysics - Earth and Planetary Astrophysics