TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica
Trifonov, Trifon; Henning, Thomas; Latham, David W.; Jordán, Andrés; Kossakowski, Diana; Brahm, Rafael; Zhou, George; Tan, Thiam-Guan; Hobson, Melissa J.; Eberhardt, Jan; Espinoza, Nestor; Schlecker, Martin; Jones, Matías I.; Lissauer, Jack J.; Collins, Karen A.; Wohler, Bill; Ricker, George R.; Vanderspek, Roland; Winn, Joshua N.; Jenkins, Jon M.; Seager, S.; Howard, Saburo; Barkaoui, Khalid; Guillot, Tristan; Abe, Lyu; Bendjoya, Philippe; Crouzet, Nicolas; Dransfield, Georgina; Gasparetto, Thomas; Günther, Maximilian N.; Suarez, Olga; Shporer, Avi; Mireles, Ismael; Korth, Judith; Dragomir, Diana; Lendl, Monika; Colón, Knicole D.; Stockdale, Chris; Sefako, Ramotholo; Bouchy, François; Schwarz, Richard P.; Goeke, Robert F.; Carleo, Ilaria; Mann, Christopher R.; Ulmer-Moll, Solène; Rojas, Felipe; Mekarnia, Djamel; Buttu, Marco; Tala Pinto, Marcelo; Saesen, Sophie; Torres Miranda, Pascal José; J. Triaud, Amaury H. M.
Germany, Chile, Bulgaria, United States, France, Belgium, Spain, Switzerland, Italy, Netherlands, United Kingdom, Sweden, Canada, South Africa, Australia
Abstract
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 ${104.854}_{-0.002}^{+0.001}\,{\rm{day}}$ 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 ${273.69}_{-0.22}^{+0.26}\,{\rm{days}}$ and an estimated mass of ${0.28}_{-0.01}^{+0.02}\,{M}_{{\rm{J}}}$ . This period places it within the conservative habitable zone.