June
2024
•
2024AJ....167..289H
Authors
•
Hori, Yasunori
•
Fukui, Akihiko
•
Hirano, Teruyuki
•
Narita, Norio
•
de Leon, Jerome P.
•
Ishikawa, Hiroyuki Tako
•
Hartman, Joel D.
•
Morello, Giuseppe
•
García, Nestor Abreu
•
Álvarez Hernández, Leticia
•
Béjar, Víctor J. S.
•
Calatayud-Borras, Yéssica
•
Carleo, Ilaria
•
Enoc, Gareb
•
Esparza-Borges, Emma
•
Fukuda, Izuru
•
Galán, Daniel
•
Geraldía-González, Samuel
•
Hayashi, Yuya
•
Ikoma, Masahiro
•
Ikuta, Kai
•
Isogai, Keisuke
•
Kagetani, Taiki
•
Kawai, Yugo
•
Kawauchi, Kiyoe
•
Kimura, Tadahiro
•
Kodama, Takanori
•
Korth, Judith
•
Kusakabe, Nobuhiko
•
Laza-Ramos, Andrés
•
Livingston, John H.
•
Luque, Rafael
•
Miyakawa, Kohei
•
Mori, Mayuko
•
Murgas, Felipe
•
Orell-Miquel, Jaume
•
Palle, Enric
•
Parviainen, Hannu
•
Peláez-Torres, Alberto
•
Puig-Subirà, Marta
•
Sánchez-Benavente, Manuel
•
Sosa-Guillén, Paula
•
Stangret, Monika
•
Terada, Yuka
•
Muñoz Torres, Sara
•
Watanabe, Noriharu
•
Bakos, Gaspar Á.
•
Barkaoui, Khalid
•
Beichman, Charles
•
Benkhaldoun, Zouhair
•
Boyle, Andrew W.
•
Ciardi, David R.
•
Clark, Catherine A.
•
Collins, Karen A.
•
Collins, Kevin I.
•
Conti, Dennis M.
•
Crossfield, Ian J. M.
•
Everett, Mark E.
•
Furlan, Elise
•
Ghachoui, Mourad
•
Gillon, Michaël
•
Gonzales, Erica J.
•
Higuera, Jesus
•
Horne, Keith
•
Howell, Steve B.
•
Jehin, Emmanuël
•
Lester, Kathryn V.
•
Lund, Michael B.
•
Matson, Rachel
•
Matthews, Elisabeth C.
•
Pozuelos, Francisco J.
•
Safonov, Boris S.
•
Schlieder, Joshua E.
•
Schwarz, Richard P.
•
Sefako, Ramotholo
•
Srdoc, Gregor
•
Strakhov, Ivan A.
•
Timmermans, Mathilde
•
Waalkes, William C.
•
Ziegler, Carl
•
Charbonneau, David
•
Essack, Zahra
•
Guerrero, Natalia M.
•
Harakawa, Hiroki
•
Hedges, Christina
•
Ishizuka, Masato
•
Jenkins, Jon M.
•
Konishi, Mihoko
•
Kotani, Takayuki
•
Kudo, Tomoyuki
•
Kurokawa, Takashi
•
Kuzuhara, Masayuki
•
Nishikawa, Jun
•
Omiya, Masashi
•
Ricker, George R.
•
Seager, Sara
•
Serizawa, Takuma
•
Striegel, Stephanie
•
Tamura, Motohide
•
Ueda, Akitoshi
•
Vanderspek, Roland
•
Vievard, Sébastien
•
Winn, Joshua N.
Abstract
•
Sub-Neptunes with radii of 2–3 R ⊕ are intermediate in size between rocky planets and Neptune-sized planets. The orbital properties and bulk compositions of transiting sub-Neptunes provide clues to the formation and evolution of close-in small planets. In this paper, we present the discovery and follow-up of four sub-Neptunes orbiting M dwarfs (TOI-782, TOI-1448, TOI-2120, and TOI-2406), three of which were newly validated by ground-based follow-up observations and statistical analyses. TOI-782 b, TOI-1448 b, TOI-2120 b, and TOI-2406 b have radii of , , 2.120 ± 0.067 R ⊕, and and orbital periods of P = 8.02, 8.11, 5.80, and 3.08 days, respectively. Doppler monitoring with the Subaru/InfraRed Doppler instrument led to 2σ upper limits on the masses of <19.1 M ⊕, <19.5 M ⊕, <6.8 M ⊕, and <15.6 M ⊕ for TOI-782 b, TOI-1448 b, TOI-2120 b, and TOI-2406 b, respectively. The mass–radius relationship of these four sub-Neptunes testifies to the existence of volatile material in their interiors. These four sub-Neptunes, which are located above the so-called "radius valley," are likely to retain a significant atmosphere and/or an icy mantle on the core, such as a water world. We find that at least three of the four sub-Neptunes (TOI-782 b, TOI-2120 b, and TOI-2406 b), orbiting M dwarfs older than 1 Gyr, are likely to have eccentricities of e ∼ 0.2–0.3. The fact that tidal circularization of their orbits is not achieved over 1 Gyr suggests inefficient tidal dissipation in their interiors.
Links
