A joint effort to discover and characterize two resonant mini-Neptunes around TOI-1803 with TESS, HARPS-N, and CHEOPS

Author(s): T. Zingales, L. Malavolta, L. Borsato, D. Turrini, A. Bonfanti, D. Polychroni, G. Mantovan, D. Nardiello, V. Nascimbeni, A. F. Lanza, A. Bekkelien, A. Sozzetti, C. Broeg, L. Naponiello, M. Lendl, A. S. Bonomo, A. E. Simon, S. Desidera, G. Piotto, L. Mancini, M. J. Hooton, A. Bignamini, J. A. Egger, A. Maggio, Y. Alibert, D. Locci, L. Delrez, F. Biassoni, L. Fossati, L. Cabona, G. Lacedelli, I. Carleo, P. Leonardi, G. Andreuzzi, A. Brandeker, R. Cosentino, A. C.M. Correia, R. Claudi, R. Alonso, M. Damasso, T. G. Wilson, T. Bárczy, M. Pinamonti, D. Baker, K. Barkaoui, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, T. Beck, C. Beichman, W. Benz, A. Bieryla, N. Billot, P. Bosch-Cabot, L. G. Bouma, D. R. Ciardi, A. Collier Cameron, K. A. Collins, Ian J.M. Crossfield, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, O. D.S. Demangeon, B. O. Demory, A. Derekas, D. Dragomir, B. Edwards, D. Ehrenreich, A. Erikson, B. Falk, A. Fortier, M. Fridlund, A. Fukui, D. Gandolfi, K. Gazeas, M. Gillon, E. Gonzales, M. Güdel, P. Guerra, M. N. Günther, A. Heitzmann, Ch Helling, S. B. Howell, K. G. Isaak, J. Jenkins, L. L. Kiss, J. Korth, K. W.F. Lam, J. Laskar, A. Lecavelier Des Etangs, D. Magrin, R. Matson, E. C. Matthews, P. F.L. Maxted, S. Mcdermott, M. Munari, C. Mordasini, N. Narita, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I. Ribas, S. Salmon, N. C. Santos, G. Scandariato, S. Seager, D. Ségransan, A. M.S. Smith, J. Schlieder, R. P. Schwarz, A. Shporer, S. G. Sousa, M. Stalport, M. Steinberger, S. Sulis, Gy M. Szabó, J. D. Twicken, S. Udry, V. Van Grootel, J. Venturini, E. Villaver, N. A. Walton, J. N. Winn
Abstract: Context. The discovery and characterization of mini-Neptunes hold a potentially crucial impact on planetary formation and evolution theories. Estimating their orbital parameters and atmospheric properties would provide valuable hints to improve formation and atmospheric models. Aims. We present the discovery of two mini-Neptunes near a 2:1 orbital resonance configuration orbiting the K0 star TOI-1803. We describe in detail their orbital architecture and suggest some possible formation and evolution scenarios. Methods. Using CHEOPS, TESS, and HARPS-N datasets, we estimated the radius and the mass of both planets. We used a multidimensional Gaussian process with a quasi-periodic kernel to disentangle the planetary components from the stellar activity in the HARPS-N dataset. We performed dynamical modeling to explain the orbital configuration and performed planetary formation and evolution simulations. For the least dense planet, we assumed different atmospheric compositions and defined possible atmospheric scenarios with simulated JWST observations. Results. TOI-1803 b and TOI-1803 c have orbital periods of ∼6.3 and ∼12.9 days, respectively, residing in close proximity to a 2:1 orbital resonance. Ground-based photometric follow-up observations have revealed significant transit timing variations (TTV) with an amplitude of ∼10 min and ∼40 min, respectively, for planets b and -c. With the masses computed from the radial velocities dataset, we obtained a density of (0.39 ± 0.10) ρ_⊕ and (0.076 ± 0.038) ρ_⊕ for planets b and -c, respectively. TOI-1803 c is among the least dense mini-Neptunes currently known, and due to its inflated atmosphere, it is a suitable target for transmission spectroscopy with JWST. With NIRSpec observations, we could understand whether the planet has kept its primary atmosphere or not, which would constrain our formation models. Conclusions. We report the discovery of two mini-Neptunes close to a 2:1 orbital resonance. The detection of significant TTVs from ground-based photometry opens scenarios for a more precise mass determination. TOI-1803 c is one of the least dense mini-Neptunes known so far, and it is of great interest among the scientific community since it could constrain current formation scenarios. JWST observations could give us valuable insights to characterize this interesting system.
Organisation(s): Department of Astrophysics
External organisation(s): University of Padova, Osservatorio Astronomico, INAF-Osservatorio Astrofisico di Torino, Österreichische Akademie der Wissenschaften (ÖAW), INAF Astronomical Observatory of Triest, INAF-Osservatorio Astrofisico di Catania, Université de Genève, Universität Bern, Università degli Studi di Roma "Tor Vergata", Max-Planck-Institut für Astronomie, University of Cambridge, Université de Liège, Katholieke Universiteit Leuven, Università degli Studi dell'Insubria, INAF Osservatorio Astronomico di Brera, Institute of Astrophysics of the Canary Islands, Università degli Studi di Trento, INAF - Osservatorio Astronomico di Roma, Instituto Nazionale die Astrofisica (INAF), Stockholm University, Universidade de Coimbra, University of La Laguna, University of Warwick, Admatis Ltd., Austin College, Massachusetts Institute of Technology, European Space Astronomy Centre (ESA), Universidade do Porto, National Aeronautics & Space Administration (NASA), Harvard-Smithsonian Center for Astrophysics, Observatori Astronòmic Albanyà, California Institute of Technology (Caltech), University of St. Andrews, University of Kansas, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Lund University, Aix-Marseille Université, Eötvös Loránd University Budapest, University of New Mexico, SRON Netherlands Institute for Space Research , Space Telescope Science Institute, Leiden University, Chalmers University of Technology, University of Tokyo, University of Turin, National & Kapodistrian University of Athens, University of California, Santa Cruz, Science and Operations Department - Science Division (SCI-SC), Technische Universität Graz, Eötvös Loránd Research Network, Lund Observatory, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Keele University, Proto-Logic LLC, National Institutes of Natural Sciences (NINS), Eidgenössische Technische Hochschule Zürich, Freie Universität Berlin (FU), Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), HUN-REN Hungarian Research Network, SETI Institute, Princeton University
Journal: Astronomy and Astrophysics
Volume: 695
No. of pages: 26
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202451180
Publication date: 03-2025
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics, 103038 Space exploration
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/c858f2d5-e6f4-4b3e-a13b-b606f782acab

Back