TOI-2525 b and c: A Pair of Massive Warm Giant Planets with Strong Transit Timing Variations Revealed by TESS

• Published in: The Astronomical journal Vol. 165; no. 4; p. 179
• Main Authors: Trifonov, Trifon, Brahm, Rafael, Jordán, Andrés, Hartogh, Christian, Henning, Thomas, Hobson, Melissa J., Schlecker, Martin, Howard, Saburo, Reichardt, Finja, Espinoza, Nestor, Lee, Man Hoi, Nesvorny, David, Rojas, Felipe I., Barkaoui, Khalid, Kossakowski, Diana, Boyle, Gavin, Dreizler, Stefan, Kürster, Martin, Heller, René, Guillot, Tristan, Triaud, Amaury H. M. J., Abe, Lyu, Agabi, Abdelkrim, Bendjoya, Philippe, Crouzet, Nicolas, Dransfield, Georgina, Gasparetto, Thomas, Günther, Maximilian N., Marie-Sainte, Wenceslas, Mékarnia, Djamel, Suarez, Olga, Teske, Johanna, Butler, R. Paul, Crane, Jeffrey D., Shectman, Stephen, Ricker, George R., Shporer, Avi, Vanderspek, Roland, Jenkins, Jon M., Wohler, Bill, Collins, Karen A., Collins, Kevin I., Ciardi, David R., Barclay, Thomas, Mireles, Ismael, Seager, Sara, Winn, Joshua N.
• Format: Journal Article
• Language: English
• Published: Madison IOP Publishing 01-04-2023
• Subjects: Astronomy; Density; Exoplanet astronomy; Exoplanet systems; Exoplanets; Jupiter; K stars; Light curve; Neptune; Orbital resonances (celestial mechanics); Orbits; Planets; Radial velocity; Transit
• ISSN: 0004-6256; 1538-3881
• DOI: 10.3847/1538-3881/acba9b

Abstract The K-type star TOI-2525 has an estimated mass of M = 0.849 − 0.033 + 0.024 M ⊙ and radius of R = 0.785 − 0.007 + 0.007 R ⊙ observed by the TESS mission in 22 sectors (within sectors 1 and 39). The TESS light curves yield significant transit events of two companions, which show strong transit timing variations (TTVs) with a semiamplitude of ∼6 hr. We performed TTV dynamical and photodynamical light-curve analysis of the TESS data combined with radial velocity measurements from FEROS and PFS, and we confirmed the planetary nature of these companions. The TOI-2525 system consists of a transiting pair of planets comparable to Neptune and Jupiter with estimated dynamical masses of m b = 0.088 − 0.004 + 0.005 and m c = 0.709 − 0.033 + 0.034 M Jup , radii of r b = 0.88 − 0.02 + 0.02 and r c = 0.98 − 0.02 + 0.02 R Jup , and orbital periods of P b = 23.288 − 0.002 + 0.001 and P c = 49.260 − 0.001 + 0.001 days for the inner and outer planet, respectively. The period ratio is close to the 2:1 period commensurability, but the dynamical simulations of the system suggest that it is outside the mean-motion resonance (MMR) dynamical configuration. Object TOI-2525 b is among the lowest-density Neptune-mass planets known to date, with an estimated median density of ρ b = 0.174 − 0.015 + 0.016 g cm −3 . The TOI-2525 system is very similar to the other K dwarf systems discovered by TESS, TOI-2202 and TOI-216, which are composed of almost identical K dwarf primaries and two warm giant planets near the 2:1 MMR.