2025A&A...700A.118F

Context. Despite predictions from planetary population synthesis models indicating that such systems should be exceedingly rare, short-period gas giants do exist around low-mass stars (T_eff < 4965 K), albeit at lower frequency than around hotter stars.
Aims. By combining data from the Transiting Exoplanet Survey Satellite (TESS) and ground-based follow-up observations, we seek to confirm and characterize giant planets transiting K dwarfs, particularly mid- to late-K dwarfs.
Methods. Photometric data were obtained from the TESS mission, supplemented by ground-based imaging and photometric observations, as well as high-resolution spectroscopic data from the CORALIE spectrograph. Radial velocity (RV) measurements were analyzed to confirm the presence of companions.
Results. We report the confirmation and characterization of three giants transiting mid-K dwarfs. Within the TOI-2969 system, a giant planet of 1.16 ± 0.04 M_Jup with a radius of 1.10 ± 0.08 R_Jup orbits its K3V host in 1.82 days. The TOI-2989 system contains a 3.0 ± 0.2 M_Jup giant with a radius of 1.12 ± 0.05 R_Jup, which orbits its K4V host in 3.12 days. The K4V star TOI-5300 hosts a giant of 0.6 ± 0.1 M_Jup with a radius of 0.88 ± 0.08 R_Jup and an orbital period of 2.3 days. The equilibrium temperatures of the companions range from 1001 to 1186 K, which classifies them as hot Jupiters. However, they do not exhibit radius inflation. The estimated heavy element masses in their interiors, inferred from the mass, radius, and evolutionary models, are 90 ± 30M_⊕, 114 ± 30M_⊕, and 84 ± 21M_⊕, respectively. These heavy element masses are significantly higher than most reported heavy elements for K-dwarf hot Jupiters.
Conclusions. These mass characterizations contribute to the poorly explored population of massive companions around low-mass stars.