{"paper":{"title":"Kilometer-precise (UII) Umbriel physical properties from the multichord stellar occultation on 2020 September 21","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.EP","authors_text":"A. Olsen, A. R. Gomes-J\\'unior, A. Scheck, B. Billard, B. E. Morgado, B. Sicardy, C. Anderson, C. Kitting, D. Ceravolo, D. di Cicco, D. Dunham, D. Gamble, D. Oesper, F. Braga-Ribas, G. Benedetti-Rossi, G. Margoti, G. Viscome, J. Bardecker, J. Bean, J. I. B. Camargo, J. Moore, K. Bender, K. Getrost, K. Green, M. Assafin, M. E. Wasiuta, N. Carlson, N. Smith, P. Ceravolo, P. Maley, R. Bria, R. Dunford, R. Nolthenius, R. Tatum, R. Venable, R. Vieira-Martins, S. Messner, S. Santos-Filho, T. George, T. Laidler, T. Swift, W. Hanna","submitted_at":"2023-10-17T12:20:47Z","abstract_excerpt":"We report the results of the stellar occultation by (UII) Umbriel on September 21st, 2020. The shadow crossed the USA and Canada, and 19 positive chords were obtained. A limb parameter accounted for putative topographic features in the limb fittings. Ellipse fittings were not robust - only upper limits were derived for the true size/shape of a putative Umbriel ellipsoid. The adopted spherical solution gives radius = 582.4 +/- 0.8 km, smaller/close to 584.7 +/- 2.8 km from Voyager II. The apparent ellipse fit results in a true semi-major axis of 584.9 +/- 3.8 km, semi-minor axes of 582.3 +/- 0."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2310.11196","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/2310.11196/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"}