{"paper":{"title":"Characterisation of the TOI-421 planetary system using CHEOPS, TESS, and archival radial velocity data","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.EP","authors_text":"A. Bonfanti, A. Brandeker, A. C. M. Correira, A. Collier Cameron, A. Deline, A. Erikson, A. E. Simon, A. F. Krenn, A. Fortier, A. Heitzmann, A. Lecavelier des Etangs, A. Leleu, A. M. S. Smith, B.-O. Demory, B. Ulmer, C. Broeg, C. Helling, C. Lovis, C. Mordasini, D. Barrado Navascues, D. Ehrenreich, D. Gandolfi, D. Kubyshkina, D. Magrin, D. Pollacco, D. Queloz, D. S\\'egransan, E. Pall\\'e, E. Villaver, G. Anglada, G. Olofsson, G. Peter, G. Piotto, G. Scandariato, Gy. M. Szab\\'o, H. Rauer, I. Pagano, I. Ribas, J. A. Egger, J. A. Patel, J. Asquier, J. Cabrera, J. Hasiba, J. Laskar, J. Venturini, K. G. Isaak, K. W. F. Lam, L. Borsato, L. Delrez, L. Fossati, L. L. Kiss, M. B. Davies, M. Beck, M. Deleuil, M. Fridlund, M. Gillon, M. G\\\"udel, M. Lendl, M. N. G\\\"unther, M. Rieder, M. Stalport, M. Steller, N. A. Walton, N. Billot, N. C. Santos, N. Rando, N. Thomas, O. D. S. Demangeon, P. E. Cubillos, P. F. L. Maxted, R. Alonso, R. Ottensamer, R. Ragazzoni, S. C. C. Barros, S. Charnoz, S. G. Sousa, S. Hoyer, S. Udry, Sz. Csizmadia, T. B\\'arczy, T. Beck, T. G. Wilson, T. Zingales, V. Adibekyan, V. Nascimbeni, V. Van Grootel, V. Viotto, W. Baumjohann, W. Benz, X. Bonfils, Y. Alibert","submitted_at":"2024-04-17T05:14:19Z","abstract_excerpt":"The TOI-421 planetary system contains two sub-Neptune-type planets and is a prime target to study the formation and evolution of planets and their atmospheres. The inner planet is especially interesting as the existence of a hydrogen-dominated atmosphere at its orbital separation cannot be explained by current formation models without previous orbital migration. We jointly analysed photometric data of three TESS sectors and six CHEOPS visits as well as 156 radial velocity data points to retrieve improved planetary parameters. We also searched for TTVs and modelled the interior structure of the"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2404.11074","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2404.11074/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}