EUROPEAN SPACE AGENCY

Discovery and Characterization of an Eccentric, Warm Saturn Transiting the Solar Analog TOI-4994

DOI: 10.3847/1538-3881/ad9b90 Bibcode: 2025AJ....169...72R

Trifonov, Trifon; Henning, Thomas; Latham, David W.; Quinn, Samuel N.; Jordán, Andrés; Brahm, Rafael; Stassun, Keivan G.; Butler, R. P.; Hobson, Melissa J.; Eberhardt, Jan; Rojas, Felipe I.; Espinoza, Nestor; Schlecker, Martin; Ziegler, Carl; Collins, Karen A.; Seager, Sara; Winn, Joshua N.; Crane, Jeffrey D.; Barkaoui, Khalid; Guillot, Tristan; Abe, Lyu; Mékarnia, Djamel; Suarez, Olga; Shporer, Avi; Collins, Kevin I.; Mireles, Ismael; Hedges, Christina; Lendl, Monika; Udry, Stéphane; Rodriguez, Joseph E.; Eastman, Jason D.; Relles, Howard M.; Bouchy, François; Kunimoto, Michelle; Charbonneau, David; Vezie, Michael; Kanodia, Shubham; Teske, Johanna K.; Figueira, Pedro; Srdoc, Gregor; Battley, Matthew P.; Psaridi, Angelica; Shectman, Steve; Rodríguez Martínez, Romy; Tala Pinto, Marcelo; Osip, David; Fairnington, Tyler R.; Beletsky, Yuri; Ulmer-Moll, SolÉne

United States, Chile, Australia, Switzerland, France, Germany, Bulgaria, Belgium, Spain, Croatia

Abstract

We present the detection and characterization of TOI-4994b (TIC 277128619b), a warm Saturn-sized planet discovered by the NASA Transiting Exoplanet Survey Satellite. TOI-4994b transits a G-type star (V = 12.6 mag) with a mass, radius, and effective temperature of , , and Teff = 5640 ± 110 K. We obtained follow-up ground-based photometry from the Las Cumbres Observatory and the Antarctic Search for Transiting ExoPlanets telescopes, and we confirmed the planetary nature of TOI-4994b with multiple radial velocity observations from the Planet Finder Spectrograph, CHIRON, High Accuracy Radial velocity Planet Searcher, Fiber-fed Extended Range Optical Spectrograph, and CORALIE instruments. From a global fit to the photometry and radial velocities, we determine that TOI-4994b is in a 21.5 day eccentric orbit (e = 0.32 ± 0.04) and has a mass of , a radius of , and a Saturn-like bulk density of . We find that TOI-4994 is a potentially viable candidate for follow-up stellar obliquity measurements. TOI-4994b joins the small sample of warm Saturn analogs and thus sheds light on our understanding of these rare and unique worlds. *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

2025 • The Astronomical Journal
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