2025/05/29 by Carl Ingebretsen, Bryce Bolin, Ingebretsen, Carl +20 · 1 voice · 3 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Earthquake Detection and Analysis #Gamma-ray bursts and supernovae #astro-ph.EP #astro-ph.IM
paper · pdf · doi:10.48550/arxiv.2505.23736
arxiv published 2025/05/29 · arxiv updated 2025/09/16
Imminent impactors may be detected only a few hours before their impact with Earth, providing a brief opportunity to characterize them before impact. We describe the characterization of imminent impactor 2024 RW1, which was discovered by the Catalina Sky Survey on 2024 September 4 at 05:43 UTC, before it entered the atmosphere near the northern Philippines at 16:39 UTC. We observed 2024 RW1 with the Astrophysical Research Consortium Telescope Imaging Camera on the Apache Point Astrophysical Research Consortium's 3.5-m telescope on 2024 September 4 10:16 UTC. We obtained g, r, i, and z photometry of 2024 RW1, yielding color indices of g-r = 0.47±0.04, r-i = 0.13±0.04, i-z = -0.11±0.07, and g-i = 0.60±0.04, corresponding to a spectral slope of 0.67±0.40~%/100 nm. The closest match to an asteroid spectral type is with B-type asteroids from the C-complex. We detect variations in the time series photometry of the asteroid with an amplitude of ∼0.75, and a double-peaked rotation period of ∼1900 s. Assuming a visible albedo of 0.07±0.03, a density of ∼1500 kg/m3, and a calculated absolute magnitude of 30.92±0.05, we estimate that the asteroid has a diameter of 3.3±0.7 m and a total mass of ∼28,000 kg. Comparing our astrometric orbital solutions to NEOMOD3, the most likely source of 2024 RW1 is the 3:1 main belt mean motion resonance (77% probability) followed by the ν6 resonance (13% probability), consistent with its organic B-type nature.