We thank an anonymous referee, whose comments led to a substantial improvement of this paper. This work was supported by the National Science Centre, Poland, through grant no. 2020/39/O/ST9/00713 This project has been supported by the Lenduelet grant LP2012-31 of the Hungarian Academy of Sciences and by the KKP-137523 Elvonal grant of the Hungarian Research,Development and Innovation Office (NKFIH). The work of JD and JH was supported by the grant 20-08218S of the Czech Science Foundation, and by the Erasmus programme of the European Union under grant number 2020-1-CZ01-KA203-078200. A. Pal and R. Szakats have received funding from the K-138962 grant of the National Research, Development and Innovation Office(NKFIH, Hungary). Erika Pakstiene and Ruta Urbonaviciute acknowledge the Europlanet 2024 RI project funded by the European Union's Horizon 2020 Research and Innovation Programme (Grant agreement No. 871149). Data from Observatorio Astronpmico do Sertao de Itaparica (OASI, Itacuruba) have been obtained with the 1-m telescope, a facility operated by the IMPACTON project of the Observatorio Nacional, Brazil. F.M., E.R., M.E., W.M., W.P. and J.M. would like to thank CNPq, FAPERJ (E-26/201.877/2020 and E-26/204.602/2021) and CAPES for their support through diverse fellowships (Brazilian funding agencies). Support by CNPq (310964/2020-2) and FAPERJ (E-26/202.841/2017 and E-26/201.001/2021) is acknowledged by D.L. We acknowledge financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia(SEV-2017-0709). Funding from Spanish projects PID2020-112789GB-I00 from AEI and Proyecto de Excelencia de la Junta de Andalucia PY20-01309 is acknowledged. This work uses data obtained from the Asteroid Light-Curve Data Exchange Format (ALCDEF) database, which is supported by funding from NASA grant 80NSSC18K0851. This work is based on data provided by the MinorPlanet Physical Properties Catalogue (MP3C) of the Observatoire de la Cpted'Azur. Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemmish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.Based on observations obtained with the MAIA camera, which was built by the Institute of Astronomy of KU Leuven, Belgium, thanks to funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no 227224 (PROSPERITY,PI: Conny Aerts) and from the Research Foundation - Flanders (FWO) grant agreement G.0410.09. The CCDs of MAIA were developed by e2v in the framework of the ESA Eddington space mission project; they were offered by ESA on permanent loan to KU Leuven (Raskin et al. 2013). This article is based on observations obtained at the Observatorio Astronpmico do Sert & atilde;o de Itaparica (OASI,Itacuruba) of the Observatorio Nacional, Brazil. The Joan Oro Telescope (TJO)of the Montsec Astronomical Observatory (OAdM) is owned by the Catalan Government and operated by the Institute for Space Studies of Catalonia (IEEC). This article is based on observations made in the Observatorios de Canarias del IAC with the 0.82 m IAC80 telescope operated on the island of Tenerife by the Instituto de Astrofisica de Canarias (IAC) in the Observatorio del Teide. r This article is based on observations made with the SARA telescopes (Southeastern Association for Research in Astronomy), whose nodes are located at the Observatorios deCanarias del IAC on the island of La Palma in the Observatorio del Roque de los Muchachos; Kitt Peak, AZ under the auspices of the National Optical Astronomy Observatory (NOAO); and Cerro Tololo Inter-American Observatory (CTIO) in La Serena, Chile. This project uses data from the Super WASP archive. The WASP project is currently funded and operated by Warwick University and Keele University, and was originally set up by Queen's University Belfast, the Universities of Keele, St. Andrews, and Leicester, the Open University, the Isaac Newton Group, the Instituto de Astrofisica de Canarias, the South African Astronomical Observatory, and by STFC. TRAPPIST-South is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant PDRT.0120.21. TRAPPIST-North is a project funded by the University of Liege, in collaboration with the Cadi Ayyad University of Marrakech (Morocco). Funding for the Kepler and K2 missions are provided by the NASA Science Mission Directorate. The data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and contracts. Data from Pic du Midi Observatory have been obtained with the 0.6-m telescope, a facility operated by Observatoire Midi Pyrenees and Association T60,an amateur association. This research is partly based on observations obtained with the 60-cm Cassegrain telescope (TC60) and 90-cm Schmidt-Cassegrain telescope (TSC90) of the Institute of Astronomy of the Nicolaus Copernicus University in Torun. We acknowledge the contributions of the occultation observers who have provided the observations in the dataset. Most of those observers are affiliated with one or more of: European Asteroidal Occultation Network(EAON), International Occultation Timing Association (IOTA), International Occultation Timing Association European Sect. (IOTA/ES), Japanese Occultation Information Network (JOIN), and Trans Tasman Occultation Alliance(TTOA).

Full list of the authors: Marciniak, A.; Ďurech, J.; Choukroun, A.; Hanuš, J.; Ogłoza, W.; Szakáts, R.; Molnár, L.; Pál, A.; Monteiro, F.; Frappa, E.; Beisker, W.; Pavlov, H.; Moore, J.; Adomavičienė, R.; Aikawa, R.; Andersson, S.; Antonini, P.; Argentin, Y.; Asai, A.; Assoignon, P.; Barton, J.; Baruffetti, P.; Bath, K. L.; Behrend, R.; Benedyktowicz, L.; Bernasconi, L.; Biguet, G.; Billiani, M.; Błażewicz, D.; Boninsegna, R.; Borkowski, M.; Bosch, J.; Brazill, S.; Bronikowska, M.; Bruno, A.; Butkiewicz-Bąk, M.; Caron, J.; Casalnuovo, G.; Castellani, J. J.; Ceravolo, P.; Conjat, M.; Delincak, P.; Delpau, J.; Demeautis, C.; Demirkol, A.; Dróżdż, M.; Duffard, R.; Durandet, C.; Eisfeldt, D.; Evangelista, M.; Fauvaud, S.; Fauvaud, M.; Ferrais, M.; Filipek, M.; Fini, P.; Fukui, K.; Gährken, B.; Geier, S.; George, T.; Goffin, B.; Golonka, J.; Goto, T.; Grice, J.; Guhl, K.; Halíř, K.; Hanna, W.; Harman, M.; Hashimoto, A.; Hasubick, W.; Higgins, D.; Higuchi, M.; Hirose, T.; Hirsch, R.; Hofschulz, O.; Horaguchi, T.; Horbowicz, J.; Ida, M.; Ignácz, B.; Ishida, M.; Isobe, K.; Jehin, E.; Joachimczyk, B.; Jones, A.; Juan, J.; Kamiński, K.; Kamińska, M. K.; Kankiewicz, P.; Kasebe, H.; Kattentidt, B.; Kim, D. -H.; Kim, M. -J.; Kitazaki, K.; Klotz, A.; Komraus, M.; Konstanciak, I.; Könyves-Tóth, R.; Kouno, K.; Kowald, E.; Krajewski, J.; Krannich, G.; Kreutzer, A.; Kryszczyńska, A.; Kubánek, J.; Kudak, V.; Kugel, F.; Kukita, R.; Kulczak, P.; Lazzaro, D.; Licandro, J.; Livet, F.; Maley, P.; Manago, N.; Mánek, J.; Manna, A.; Matsushita, H.; Meister, S.; Mesquita, W.; Messner, S.; Michelet, J.; Michimani, J.; Mieczkowska, I.; Morales, N.; Motyliński, M.; Murawiecka, M.; Newman, J.; Nikitin, V.; Nishimura, M.; Oey, J.; Oszkiewicz, D.; Owada, M.; Pakštienė, E.; Pawłowski, M.; Pereira, W.; Perig, V.; Perła, J.; Pilcher, F.; Podlewska-Gaca, E.; Polák, J.; Polakis, T.; Polińska, M.; Popowicz, A.; Richard, F.; Rives, J. J.; Rodrigues, T.; Rogiński, Ł.; Rondón, E.; Rottenborn, M.; Schäfer, R.; Schnabel, C.; Schreurs, O.; Selva, A.; Simon, M.; Skiff, B.; Skrutskie, M.; Skrzypek, J.; Sobkowiak, K.; Sonbas, E.; Sposetti, S.; Stuart, P.; Szyszka, K.; Terakubo, K.; Thomas, W.; Trela, P.; Uchiyama, S.; Urbanik, M.; Vaudescal, G.; Venable, R.; Watanabe, Ha.; Watanabe, Hi.; Winiarski, M.; Wróblewski, R.; Yamamura, H.; Yamashita, M.; Yoshihara, H.; Zawilski, M.; Zelený, P.; Żejmo, M.; Żukowski, K.; Żywica, S.

Context. As evidenced by recent survey results, the majority of asteroids are slow rotators (spin periods longer than 12 h), but lack spin and shape models because of selection bias. This bias is skewing our overall understanding of the spins, shapes, and sizes of asteroids, as well as of their other properties. Also, diameter determinations for large (>60 km) and medium-sized asteroids (between 30 and 60 km) often vary by over 30% for multiple reasons. Aims. Our long-term project is focused on a few tens of slow rotators with periods of up to 60 h. We aim to obtain their full light curves and reconstruct their spins and shapes. We also precisely scale the models, typically with an accuracy of a few percent. Methods. We used wide sets of dense light curves for spin and shape reconstructions via light-curve inversion. Precisely scaling them with thermal data was not possible here because of poor infrared datasets: large bodies tend to saturate in WISE mission detectors. Therefore, we recently also launched a special campaign among stellar occultation observers, both in order to scale these models and to verify the shape solutions, often allowing us to break the mirror pole ambiguity. Results. The presented scheme resulted in shape models for 16 slow rotators, most of them for the first time. Fitting them to chords from stellar occultation timings resolved previous inconsistencies in size determinations. For around half of the targets, this fitting also allowed us to identify a clearly preferred pole solution from the pair of two mirror pole solutions, thus removing the ambiguity inherent to light-curve inversion. We also address the influence of the uncertainty of the shape models on the derived diameters. Conclusions. Overall, our project has already provided reliable models for around 50 slow rotators. Such well-determined and scaled asteroid shapes will, for example, constitute a solid basis for precise density determinations when coupled with mass information. Spin and shape models in general continue to fill the gaps caused by various biases.© 2023 Authors

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