We report the discovery and characterization of three transiting giant planets in the TIC118798035 system. The three planets were identified as transiting candidates from data of the TESS mission, and confirmed with ground-based photometric transit observations along with radial velocity variations obtained with FEROS, HARPS and ESPRESSO. The three planets present transit timing variations (TTVs). We performed a N-body orbital fitting to the TTVs and radial velocities finding that TIC118798035 b is as warm low-density Neptune with a mass of 0.0250±0.0023 MJ, a radius of 0.655±0.018 RJ, and an orbital period of 11.507 d; TIC118798035 c is a warm Saturn with a mass of 0.403±0.024 MJ, a radius of 0.973±0.023 RJ, and an orbital period of 22.564 d; and TIC118798035 d is a warm Jupiter with a mass of 0.773±0.052 MJ, a radius of 0.923±0.044 RJ, and an orbital period of 48.925 d. The bulk metallicities of the three planets don't fully follow the mass-metallicity correlation found for the giant planets of the solar system, which hints at a somewhat different formation history for the planets of the TIC118798035 system. TIC118798035 is the only system having more than two transiting planets larger than 0.5 RJ with a precise orbital and physical characterization, amenable for future atmospheric studies.
@article{arxiv.2510.19162,
title = {A Compact Multi-Planet System of Three Transiting Giant Planets Around TIC118798035},
author = {Rafael Brahm and Trifon Trifonov and Andrés Jordán and Thomas Henning and Néstor Espinoza and Felipe I. Rojas and Marcelo Tala Pinto and Matías I. Jones and Daniel Thorngren and Lorena Acuña and Jan Eberhardt and Yared Reinarz and Helem Salinas and Michaela Vítková and Juan I. Espinoza-Retamal and Gaspar Bakos and Attila Bódi and Gavin Boyle and Zoltan Csubry and Joel Hartman and Anthony Keyes and Vincent Suc and Geert Jan Talens},
journal= {arXiv preprint arXiv:2510.19162},
year = {2025}
}