학술논문
A close-in puffy Neptune with hidden friends: The enigma of TOI 620
Document Type
Working Paper
Author
Reefe, Michael A.; Luque, Rafael; Gaidos, Eric; Beard, Corey; Plavchan, Peter P.; Cointepas, Marion; Cale, Bryson L.; Palle, Enric; Parviainen, Hannu; Feliz, Dax L.; Eastman, Jason; Stassun, Keivan; Gagné, Jonathan; Jenkins, Jon M.; Boyd, Patricia T.; Kidwell, Richard C.; McDermott, Scott; Collins, Karen A.; Fong, William; Guerrero, Natalia; Almenara-Villa, Jose-Manuel; Bean, Jacob; Beichman, Charles A.; Berberian, John; Bieryla, Allyson; Bonfils, Xavier; Bouchy, François; Brady, Madison; Bryant, Edward M.; Cacciapuoti, Luca; Cañas, Caleb I.; Ciardi, David R.; Collins, Kevin I.; Crossfield, Ian; Dressing, Courtney D.; Eigmueller, Philipp; Mufti, Mohammed El; Esparza-Borges, Emma; Fukui, Akihiko; Gao, Peter; Geneser, Claire; Gnilka, Crystal L.; Gonzales, Erica; Gupta, Arvind F.; Halverson, Sam; Hearty, Fred; Howell, Steve B.; Irwin, Jonathan; Kanodia, Shubham; Kasper, David; Kodama, Takanori; Kostov, Veselin; Latham, David W.; Lendl, Monika; Lin, Andrea; Livingston, John H.; Lubin, Jack; Mahadevan, Suvrath; Matson, Rachel; Matthews, Elisabeth; Murgas, Felipe; Narita, Norio; Newman, Patrick; Ninan, Joe; Osborn, Ares; Quinn, Samuel N.; Robertson, Paul; Roy, Arpita; Schlieder, Joshua; Schwab, Christian; Seifahrt, Andreas; Smith, Gareth D.; Sohani, Ahmad; Stefánsson, Guðmundur; Stevens, Daniel; Stürmer, Julian; Tanner, Angelle; Terrien, Ryan; Teske, Johanna; Vermilion, David; Wang, Sharon X.; Wittrock, Justin; Wright, Jason T.; Zechmeister, Mathias; Zohrabi, Farzaneh
Source
AJ, 163(6), 269 (2022)
Subject
Language
Abstract
We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA TESS mission. We utilize photometric data from both TESS and ground-based follow-up observations to validate the ephemerides of the 5.09-day transiting signal and vet false positive scenarios. High-contrast imaging data are used to resolve the stellar host and exclude stellar companions at separations $\gtrsim 0.2''$. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with multiple PRV spectrographs to confirm the planetary nature of the transiting exoplanet. We calculate a 5$\sigma$ upper limit of $M_P < 7.1$ M$_\oplus$ and $\rho_P < 0.74$ g cm$^{-3}$, and we identify a non-transiting 17.7-day candidate. We also find evidence for a substellar (1-20 M$_{\rm J}$) companion with a projected separation $\lesssim 20$ au from a combined analysis of Gaia, AO imaging, and RVs. With the discovery of this outer companion, we carry out a detailed exploration of the possibilities that TOI 620 b might instead be a circum-secondary planet or a pair of eclipsing binary stars orbiting the host in a hierarchical triple system. We find, under scrutiny, that we can exclude both of these scenarios from the multi-wavelength transit photometry, thus validating TOI 620 b as a low-density exoplanet transiting the central star in this system. The low density of TOI 620 b makes it one of the most amenable exoplanets for atmospheric characterization, such as with JWST and Ariel, validated or confirmed by the TESS mission to date.
Comment: 64 pages, 34 figures, 22 tables. Accepted for publication in the Astronomical Journal
Comment: 64 pages, 34 figures, 22 tables. Accepted for publication in the Astronomical Journal