Detection and characterisation of binary asteroid candidates through stellar occultations
Year: 2026
Type: article
Abstract: Context . Binary asteroids provide key access to fundamental parameters of Solar System remnants and planetary formations. However, the current knowledge of binary asteroids remains strongly biased by observational limitations, and main belt binary systems are still poorly characterised since current techniques preferentially detect either widely separated binaries through direct imaging or close and bright systems via photometry and radar for near-Earth asteroids. In this context, the high-precision astrometry of the Gaia mission has revealed a new population of candidate binaries exhibiting dynamical signatures consistent with unresolved companions. Stellar occultations have therefore emerged as one of the most effective methods to confirm the binary nature of a candidate and improve the current census of intermediate-size systems. Aims . This work is part of the GaiaMoons program, and our aim with it was to characterise a sample of 357 potential binary asteroid targets and confirm or refute their binary nature. The properties of these candidates were derived from the high-precision photometric and astrometric observations provided by the Gaia satellite. Methods . We adopted stellar occultation as the observational method to study these targets. Between October 2023 and February 2026, we successfully carried out 165 observations for 101 targets. We subsequently analysed these events in the context of the available literature and previously reported observations. Results . Out of the 165 observations, 76 led at least to one positive observation. Among these, 33 had at least two positives for 24 objects that have undergone unprecedented occultation observation campaigns, with four objects showing indications of binary or contact binary features, namely (1127) Mimi, (35420) 1998 AG 6 , (206) Hersilia, and (36882) 2000 SW 155 . For the vast majority of these objects, the resulting dataset from all reduced observations provides unique physical and astrometric constraints, as they had never been observed through stellar occultations before. In addition, 89 observations with only negatives allowed the near environment of the targets to be probed. Conclusions . GaiaMoons illustrates how stellar occultation campaigns associated with Gaia observations generate a self-improving cycle to find new binary, thereby probing size and shape to constrain future observations. By standardising this approach, we deliver critical data in unexplored parameter spaces, resolving long-standing observational ambiguities.
Source: Astronomy and Astrophysics
Authors: R. Lallemand, J. Desmars, B. Sicardy, Z. Liu, P. Tanga, L. Liberato, B. Carry, A. Leroy, Y. Kilic, M. Assafin, A. Siakas, L. Abe, D. Mary, F. Casarramona, D. Smith, D. Antuszewicz, J.-L. Dauvergne, G. Langin, P. Henarejos, P.-L. Phan, F. Braga-Ribas, A. Castro, A. Pal, Á. Sódor, A. Cano Ruiz, A. Pratt, A. Noschese, A. Manna, A. Eberle, A. Schweizer, A. Wendelborn, A. Marciniak, B. Ziółkowski, B. Begiçarslan, B. Kattentidt, C. T. Tezcan, C. Weber, C. Schnabel, C. A. Domingues, C. Ziolek, C. Sartini, C. M. Schäfer, C. McPartlin, Cs. Kiss, D. Blazewicz, D. Deneuchatel, D. Herald, D. W. Dunham, D. Sailing, E. Fonseca Morato, E. Fernandez-Garcia, E. Smith, E. Gradovski, E. Donate Lucas, E. García Navarro, E. Kaan Ülgen, F. Garcia, F. Genc, G. Margoti, G. Arraras, G. Schmidt, G. Privett, G. Krannich, G. Lyzenga, H. de Groot, I. Pérez-Garcia, I. Z. Kelkitli, J. Mánek, J. Flores-Martín, J. Prat, J. Bardecker, J. Siegert, J. Dunham, J. Moore, J. A. Reyes, J. L. Maestre, J. L. Ortiz, J. Perła, J. Spagnotto, K. Getrost, K.-L. Bath, K. Okasaki, K. Bender, M. OConnell, M. Skrutskie, M. Jennings, M. Margoti, M. Içen, M. Acar, M. Fidêncio Neto, M. Altan, M. Rottenborn, M. Turchenko, M. A. Alava Amat, M. Kretlow, M. Tekkesinoglu, N. Takács, N. Castro-Morales, N. Morales, O. Erece, O. Canales Moreno, P. Santos Sanz, P. Fini, P. D. Maley, P. Teckenburg, P. Walker, P. Martorell, P. Gilge, P. Zeleny, P. Stuart, A. Ashimbekova, P. Denyer, R. Sfair, R. Nolthenius, R. Piety, R. Liu, R. Jones, R. Szakáts, R. Gonçalves, S. Pastor, S. Chairetas, S. Kalkan, S. Özel, S. Ötken, S. Aliş, S. Tsavdaridis, S. Meister, S. Sposetti, S. Conard, S. Tirak, S. Fisek, T. Swift, T. Haymes, T. Janík, V. Nikitin, W. Hanna, R. Dahoumane, W. Ogloza, W. Stewart, W. Beisker, Y. Liu, Y. Avcioglu, S. Quinet, J.-F. Counilh, M. Irzyk, C. Marlot, A. Keijzer, Y. Pinard, T. Salomon, T. Mollier, S. Valat, S. Kindt, J. Souchu, S. Vasseur, R. Dequinze, P. Couvée, P. Lemoine, P. Barroy, P.-J. Mercier, P. André, P. Le Guen, O. Schreurs, M. Boutet, M. Giraud, M. Lecossois, M. Serrau, M. Conjat, L. Herrier, L. Rousselot, J. Delpau, J. Bourgeois, J.-C. Dalouzy, J.-F. Gout, J.-F. Pittet, J.-F. Coliac, J.-L. Dumont, J.-P. Nombret, J.-P. Masini, J.-P. Arnould, J.-B. Marquette, G. Arlic, F. Denjean, F. Cavaillé, E. Barbotin, D. Bourdens, D. Walliang, I. Auvray, C. Latgé, C. Lavault, A. Stachowicz, E. Jacquet, C. Rizand, J. Raffard, M. Saillenfest, K. Hussein, M. Montargès, N. Robichon, S. Renner, V. Lapeyrére, W. Thuillot, F. Vachier, D. Hestroffer, A. Vienne, J. Vaubaillon, C. Bourdens, R. Boninsegna, M.-C. Lin, Y.-L. Chen, S. H. Tsai, C.-E. Lee, Y.-N. Lee, Z.-Y. Lin, H.-C. Lin, C.-H. Wang, A. T. L. Shen, T.-H. Chuang, C.-C. Chang, Ha. Watanabe, M. Ida, H. Togashi, A. Asai, T. Nemoto, K. Hosoi, Hi. Watanabe, K. Isobe, H. Yoshihara, T. Horikawa, K. Kitazaki, M. Takimoto, H. Yamamura, M. Yamashita, F. Yoshida, F. Gourdon
Institutions: Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, Laboratoire Temps Espace, Institut Polytechnique des Sciences Avancées, Université Côte d'Azur, Lagrange Laboratory, Observatoire de la Côte d’Azur, Consejo Superior de Investigaciones Científicas, Université Paris Cité, CY Cergy Paris Université, Instituto de Astrofísica de Andalucía, Universidade Federal do Rio de Janeiro, Valongo Observatory, Laboratório Interinstitucional de e-Astronomia, Aristotle University of Thessaloniki, Association française d'astronomie, University of Bologna, Universidade Tecnológica Federal do Paraná, Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, British Astronomical Association, Stuttgart Observatory, Adam Mickiewicz University in Poznań, Istanbul University, University of Tübingen, Eötvös Loránd University, National Observatory, Ministry of Science, Technology and Innovation, Calar Alto Observatory, European Southern Observatory, European Southern Observatory, Comunidad Autónoma de la Región de Murcia, Cabrillo College, Universidade Federal do Paraná, Institute of Modern Technologies and Economy, Universidade de São Paulo, Eskisehir Technical University, Deutsches Zentrum für Astrophysik, Atatürk University, Pontificia Universidad Católica de Chile, Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK National Observatory, National Aeronautics and Space Administration, Johnson Space Center, Universität Hamburg, Universidade Estadual Paulista (Unesp), Ondokuz Mayıs University, Université Laval, European Molecular Biology Network (EMBnet), Université de Picardie Jules Verne, Université de Rouen Normandie, National Tsing Hua University, National Taiwan Normal University, National Central University, University of Occupational and Environmental Health Japan, Chiba Institute of Technology
Language: English
Topic: Astro and Planetary Science
Subfield: Space and Planetary Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: European Space Agency, Agence Nationale de la Recherche, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Observatoire de Paris, Université de Recherche Paris Sciences et Lettres, Agencia Estatal de Investigación
OpenAlex ID: W7164408783