TOI-199 b : A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica

• Published in: The Astronomical Journal
• Main Authors: Hobson, Melissa J., Trifonov, Trifon, Henning, Thomas, Jordán, Andrés, Rojas, Felipe, Espinoza, Nestor, Brahm, Rafael, Eberhardt, Jan, Jones, Matías I., Mekarnia, Djamel, Kossakowski, Diana, Schlecker, Martin, Pinto, Marcelo Tala, Torres Miranda, Pascal José, Abe, Lyu, Barkaoui, Khalid, Bendjoya, Philippe, Bouchy, François, Buttu, Marco, Carleo, Ilaria, Collins, Karen A., Colón, Knicole D., Crouzet, Nicolas, Dragomir, Diana, Dransfield, Georgina, Gasparetto, Thomas, Goeke, Robert F., Guillot, Tristan, Günther, Maximilian N., Howard, Saburo, Jenkins, Jon M., Korth, Judith, Latham, David W., Lendl, Monika, Lissauer, Jack J., Mann, Christopher R., Mireles, Ismael, Ricker, George R., Saesen, Sophie, Schwarz, Richard P., Seager, S., Sefako, Ramotholo, Shporer, Avi, Stockdale, Chris, Suarez, Olga, Tan, Thiam Guan, Amaury, Amaury H.M., Ulmer-Moll, Solène, Vanderspek, Roland, Winn, Joshua N., Wohler, Bill, Zhou, George
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2023
• Subjects: Astronomy; Astrophysics and Cosmology; Saturn; Antarc*; Antarctica
• Online Access: https://lup.lub.lu.se/record/53b2ae60-c1fb-4141-93c7-3ccfda122170; https://doi.org/10.3847/1538-3881/acfc1d

We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5 hr long transit, PEST, Hazelwood, and LCO; space photometry from NEOSSat; and radial velocities (RVs) from FEROS, HARPS, CORALIE, and CHIRON. Orbiting a late G-type star, TOI-199 b has a 104.854 − 0.002 + 0.001 day period, a mass of 0.17 ± 0.02 M J, and a radius of 0.810 ± 0.005 R J. It is the first warm exo-Saturn with a precisely determined mass and radius. The TESS and ASTEP transits show strong transit timing variations (TTVs), pointing to the existence of a second planet in the system. The joint analysis of the RVs and TTVs provides a unique solution for the nontransiting companion TOI-199 c, which has a period of 273.69 − 0.22 + 0.26 days and an estimated mass of 0.28 − 0.01 + 0.02 M J . This period places it within the conservative habitable zone.