TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica
Mélissa J. Hobson, Trifon Trifonov, Thomas Henning, Andrés Jordán, Felipe Rojas, Néstor Espinoza, Rafael Brahm, Jan Eberhardt, M. I. Jones, D. Mékarnia, D. Kossakowski, Martin Schlecker, Marcelo Tala Pinto, P. Torres, Lyu Abe, Khalid Barkaoui, Philippe Bendjoya, F. Bouchy, Marco Buttu, I. Carleo, Karen A. Collins, Knicole D. Colón, Nicolas Crouzet, Diana Dragomir, Georgina Dransfield, Thomas Gasparetto, Robert F. Goeke, T. Guillot, Maximilian N. Günther, Saburo Howard, Jon M. Jenkins, J. Korth, David W. Latham, M. Lendl, Jack J. Lissauer, Christopher R. Mann, Ismael Mireles, G. Ricker, S. Saesen, Richard P. Schwarz, Sara Seager, Ramotholo Sefako, Avi Shporer, Chris Stockdale, Olga Suárez, Thiam-Guan Tan, A. H. M. J. Triaud, Soléne Ulmer-Moll, R. Vanderspek, Joshua N. Winn, Bill Wohler, George Zhou
Abstract
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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>104.854</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.002</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.001</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:mrow> <mml:mi mathvariant="normal">day</mml:mi> </mml:mrow> </mml:math> 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>273.69</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.22</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.26</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:mrow> <mml:mi mathvariant="normal">days</mml:mi> </mml:mrow> </mml:math> and an estimated mass of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>0.28</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.01</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.02</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">J</mml:mi> </mml:mrow> </mml:msub> </mml:math> . This period places it within the conservative habitable zone.