A1 Refereed original research article in a scientific journal
Astrometric Follow-up of Near-Earth Asteroid 2024 YR4 During a Torino Scale Level 3 Alert
Authors: Micheli, Marco; Devogèle, Maxime; Denneau, Larry; Ryan, Eileen V.; Ryan, William H.; Pravec, Petr; Hornoch, Kamil; Kučáková, Hana; Fatka, Petr; Brucker, Melissa J.; Lejoly, Cassandra; Moskovitz, Nicholas; Granvik, Mikael; Gray, Zuri; Fedorets, Grigori; Djupvik, Anlaug Amanda; Fuls, Carson; Rankin, David; Wierzchoś, Kacper; Gray, Bill; Lister, Tim; Wainscoat, Richard J.; Weryk, Robert; Hainaut, Olivier R.; Spoto, Federica; Veres, Peter; Rivkin, Andrew S.; Holler, Bryan J.; Burdanov, Artem Y.; de Wit, Julien; Farnocchia, Davide; Rudawska, Regina; Alonso, Peleato Eduardo; Ocaña, Francisco; Tonry, John; Audenaert, Jeroen; Faggioli, Laura; Gianotto, Francesco; Fenucci, Marco; Conversi, Luca; Moissl, Richard
Publisher: Springer Science and Business Media LLC
Publication year: 2026
Journal: Journal of the Astronautical Sciences
Article number: 8
Volume: 73
Issue: 1
ISSN: 0021-9142
eISSN: 2195-0571
DOI: https://doi.org/10.1007/s40295-025-00541-3
Publication's open availability at the time of reporting: No Open Access
Publication channel's open availability : Partially Open Access publication channel
Web address : https://doi.org/10.1007/s40295-025-00541-3
The discovery of 2024 YR4 presented the planetary defense community with the most significant impact threat in almost two decades, reaching level 3 on the Torino scale. The community, now mature and well-organized, responded with a global observational effort. Astrometric measurements, forming the basis for orbital refinement and impact prediction, were a central component of this response. In this paper, we present the astrometric data collected by the international community, from the time of discovery until the object became too faint for all existing observational assets, including JWST. We also discuss the coordination role played by the International Asteroid Warning Network, and the importance of publicly available image archives to enable precovery searches.
Funding information in the publication:
Data from the MPC’s database is made freely available to the public. Funding for this data and the MPC’s operations comes from a NASA PDCO grant (80NSSC22M0024), administered via a University of Maryland - SAO subaward (106075-Z6415201). The MPC’s computing equipment is funded in part by the above award, and in part by funding from the Tamkin Foundation. This work is partly based on observations collected at the European Southern Observatory under ESO programmes 113.2690.006, 113.2690.002 and 114.28HT.001. The authors are grateful to the Paranal staff for their dedication in obtaining our NEO observations for these programmes. This work is partly based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program #9239. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. Program GN-2025A-DD-103 based on observations obtained at the international Gemini Observatory, a program of NSF NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the U.S. National Science Foundation on behalf of the Gemini Observatory partnership: the U.S. National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). Based on observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The NOT data were obtained under program ID P68-803. The data presented here were obtained in part with ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOT. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by NASA’s Science Mission directorate. Funding for the data taken by the Magdalena Ridge Observatory (MRO) is supported by NASA PDCO grant 80NSSC24K0324. The observations by P. Pravec and his team with the 1.54m Danish Telescope on La Silla were supported by the Praemium Academiae award (no. AP2401) from the Academy of Sciences of the Czech Republic. N.M. acknowledges support from NASA YORPD grant 80NSSC21K1328, awarded to the Mission Accessible Near-Earth Object Survey (MANOS). D.F. conducted this research at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004).
