Discovery and physical characterization as the first response to a potential asteroid collision: The case of 2023 DZ<sub>2</sub>
Marcel Popescu, O. Văduvescu, J. de León, C. de la Fuente Marcos, R. de la Fuente Marcos, M. Stǎnescu, M. R. Alarcón, M. Serra Ricart, J. Licandro, D. Berteşteanu, M. Predatu, Lucian Curelaru, Freya Barwell, Kiran Jhass, Costin Radu Boldea, Amadeo Aznar Macías, L. Hudin, Bogdan Alexandru Dumitru
Abstract
Context. Near-Earth asteroids (NEAs) that may evolve into impactors deserve detailed threat assessment studies. Early physical characterization of a would-be impactor may help in optimizing impact mitigation plans. We first detected NEA 2023 DZ 2 on 27 February 2023. After that, it was found to have a minimum orbit intersection distance (MOID) with Earth of 0.00005 au as well as an unusually high initial probability of becoming a near-term (in 2026) impactor. Aims. We perform a rapid but consistent dynamical and physical characterization of 2023 DZ 2 as an example of a key response to mitigating the consequences of a potential impact. Methods. We used a multi-pronged approach, drawing from various methods (observational-computational) and techniques (spectroscopy-photometry from multiple instruments), and bringing the data together to perform a rapid and robust threat assessment. Results. The visible reflectance spectrum of 2023 DZ 2 is consistent with that of an X-type asteroid. Light curves of this object obtained on two different nights give a rotation period P = 6.2743 ± 0.0005 min with an amplitude A = 0.57 ± 0.14 mag. We confirm that although its MOID is among the smallest known, 2023 DZ 2 will not impact Earth in the foreseeable future as a result of secular near-resonant behaviour. Conclusions. Our investigation shows that coordinated observation and interpretation of disparate data provides a robust approach from discovery to threat assessment when a virtual impactor is identified. We prove that critical information can be obtained within a few days after the announcement of the potential impactor.