CAFE follow-up of TESS hot Jupiter candidates left behind: I. Five newly confirmed planets and a false positive

September 2026 • 2026A&A...713A.272L

Authors • Lillo-Box, J. • Cifuentes, C. • Balsalobre-Ruza, O. • Montesinos, B. • Latham, D. • Collins, K. A. • Ciardi, D. • Hébrard, G. • Yee, S. W. • Guenther, E. W. • Bouy, H. • Winn, J. N. • Howell, S. B. • Ziegler, C. • Everett, M. E. • Safonov, B. • Murgas, F. • Narita, N. • Nielsen, L. D. • Abreu, A. • Aceituno, J. • Agüí Fernández, J. F. • Azzaro, M. • Barrado, D. • Benni, P. • Bieryla, A. • Chontos, A. • Clark, C. A. • Delgado-Mena, E. • Deveny, S. J. • Forés-Toribio, R. • Flores-Martín, J. • Garmash, A. • Góngora, S. • D. Hartman, J. • Haukes, C. • Heidari, N. • Helm, I. J. • Kielkopf, J. F. • Köhler, J. • Littlefield, C. • Lund, M. B. • Massey, B. • Masson, A. • McCormac, J. • Morales-Calderón, M. • Mori, M. • Muñoz, J. A. • Pallé, E. • Plavchan, P. • Reefe, M. • Schlieder, J. E. • Srdoc, G. • Stockdale, C. • van Eyken, J. C. • West, R. G. • Wilkin, F. P. • Wittrock, J. • Zora, D.-V.

Abstract • Context. Hot Jupiters are key targets for understanding planet formation, migration, and atmospheres. Yet most of the ground-based observational resources for the follow-up of the TESS mission are focused on the confirmation of low-mass planet candidates. This leaves the more massive planets, such as hot Jupiters, without mass determinations and definitive confirmations. Aims. We used the CAFE₂ spectrograph at the Calar Alto Observatory to monitor the radial velocity of stars with hot-Jupiter candidates that have been left behind by follow-up efforts with the goal of confirming their planetary nature. Here, we present the results for seven candidates. Methods. We monitored the radial velocity of the seven candidate host stars TOI-603, TOI-1137, TOI-1837, TOI-2114, TOI-4492, TOI-5806, and TOI-5811. Each hosts a hot-Jupiter candidate detected by the TESS mission. We characterized these stars and jointly modeled the CAFE₂ RVs and the TESS photometric data to unravel the nature of the transiting objects and to infer their properties. Results. The objects we confirmed to be new planets are TOI-603 b (mass 33.0^+6.5_-6.2 M_⊕, period 16.2 d); TOI-2114 b (1.01^+0.14_-0.12 M_Jup, 6.2 d); TOI-4492 b (5.92^+0.67_-0.64 M_Jup, 4.4 d); TOI-5806 b (2.77^+0.34_-0.32 M_Jup, 3.2 d); and TOI-5811 B b (0.81^+0.11_-0.10 M_Jup, 6.3 d). Based on their masses and periods, TOI-603 b is a member of the ``Neptune savanna'', while TOI-2114 b, TOI-4492 b, TOI-5806 b, and TOI-5811 B b are hot Jupiters orbiting slightly evolved stars. We found the candidate TOI-5811.01 to actually be a planet orbiting the nearby bound companion TOI-5811 B. We also identified a bound stellar companion to TOI-5806 at a projected separation of 248 au, thus both form satellite-type planetary systems. As for the two remaining candidates, TOI-1837.01 is definitely an eclipsing binary, while the nature of TOI-1137.01 remains indeterminate. Conclusions. The five newly confirmed planets orbit relatively bright stars (G = 8.6--10.2 mag), and four of them are excellent candidates for atmospheric studies (with transmission spectroscopy metrics exceeding 90 for TOI-603 b, TOI-2114 b, TOI-5806 b, and TOI-5811 B b). The complex configurations of all of these systems underscore the need for intensive follow-up efforts to clarify the nature of transiting planet candidates.

Links

• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361/202660710/postscript
• DATA https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/713/A272
• PDF https://www.aanda.org/10.1051/0004-6361/202660710/pdf
• ELECTR https://doi.org/10.1051%2F0004-6361%2F202660710