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arXiv · 2412.05609

TOI-4504: Exceptionally large Transit Timing Variations induced by two resonant warm gas giants in a three planet system

Michaela Vítková·Rafael Brahm·Trifon Trifonov·Petr Kabáth·Andrés Jordán·Thomas Henning·Melissa J. Hobson·Jan Eberhardt·Marcelo Tala Pinto·Felipe I. Rojas·Nestor Espinoza·Martin Schlecker·Matías I. Jones·Maximiliano Moyano·Susana Eyheramendy·Carl Ziegler·Jack J. Lissauer·Andrew Vanderburg·Karen A. Collins·Bill Wohler·David Watanabe·George R. Ricker·Roland Vanderspek·Sara Seager·Joshua N. Winn·Jon M. Jenkins·Marek Skarka
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Abstract

We present a joint analysis of TTVs and Doppler data for the transiting exoplanet system TOI-4504. TOI-4504 c is a warm Jupiter-mass planet that exhibits the largest known transit timing variations (TTVs), with a peak-to-node amplitude of $\sim$ 2 days, the largest value ever observed, and a super-period of $\sim$ 930 d. TOI-4504 b and c were identified in public TESS data, while the TTVs observed in TOI-4504 c, together with radial velocity (RV) data collected with FEROS, allowed us to uncover a third, non-transiting planet in this system, TOI-4504 d. We were able to detect transits of TOI-4504 b in the TESS data with a period of 2.4261$\pm 0.0001$ days and derive a radius of 2.69$\pm 0.19$ R$_{\oplus}$. The RV scatter of TOI-4504 was too large to constrain the mass of TOI-4504 b, but the RV signals of TOI-4504 c \& d were sufficiently large to measure their masses. The TTV+RV dynamical model we apply confirms TOI-4504 c as a warm Jupiter planet with an osculating period of 82.54$\pm 0.02$ d, mass of 3.77$\pm 0.18$ M$_{\rm J}$ and a radius of 0.99$\pm 0.05$ R$_{\rm J}$, while the non-transiting planet TOI-4504 d, has an orbital period of 40.56$\pm 0.04$ days and mass of 1.42$_{-0.06}^{+0.07}$ M$_{\rm J}$. We present the discovery of a system with three exoplanets: a hot sub-Neptune and two warm Jupiter planets. The gas giant pair is stable and likely locked in a first-order 2:1 mean-motion resonance (MMR). The TOI-4504 system is an important addition to MMR pairs, whose increasing occurrence supports a smooth migration into a resonant configuration during the protoplanetary disk phase.

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Michaela Vítková, Rafael Brahm, Trifon Trifonov, Petr Kabáth, Andrés Jordán, Thomas Henning, Melissa J. Hobson, Jan Eberhardt, Marcelo Tala Pinto, Felipe I. Rojas, Nestor Espinoza, Martin Schlecker, Matías I. Jones, Maximiliano Moyano, Susana Eyheramendy, Carl Ziegler, Jack J. Lissauer, Andrew Vanderburg, Karen A. Collins, Bill Wohler, David Watanabe, George R. Ricker, Roland Vanderspek, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Marek Skarka. 2024-12-07. TOI-4504: Exceptionally large Transit Timing Variations induced by two resonant warm gas giants in a three planet system. https://doi.org/10.3847/2041-8213%2Fad9a53

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