JWST Observations of Potentially Hazardous Asteroid 2024 YR4
A. S. Rivkin, Thomas Mueller, Eric MacLennan, Bryan J. Holler, Artem Burdanov, Julien de Wit, Petr Pravec, M. Micheli, Maxime Devogèle, L. Conversi, Cristina A. Thomas, Davide Farnocchia, Jessie Dotson, Lorien Wheeler, Heidi B. Hammel, Stefanie N. Milam, J. de Leon, Allison K. Glantzberg
Abstract
Abstract The destructive power of an impacting asteroid is primarily estimated by knowledge of its size. Asteroid 2024 YR4 reached a peak 2032 impact probability with Earth of 3%, motivating a desire to determine its size. Owing to its infrared capabilities, JWST is uniquely suited for such assessment, especially for decameter-scale objects. We used JWST to observe 2024 YR4 and find a diameter of 60 ± 7 m. This size range corresponds to an albedo for 2024 YR4 of 8%–18%, consistent with observation that it is an S-type asteroid (International Asteroid Warning Network, https://iawn.net/obscamp/2024YR4/index.shtml ), if at the low-albedo end of that asteroid taxon. Future observations through 2025 May will help further refine the asteroid’s thermophysical model.