2011/04/27 by Dennis Bodewits, D. Bodewits, M. S. Kelley +7 · 3 citations
Physics and Astronomy · #Asteroid #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Brightness #Ejecta #Geology #Optics #Photometry (optics) #Physics #Planetary Science and Exploration #Stellar, planetary, and galactic studies #Supernova #Wavelength #astro-ph.EP
paper · pdf · doi:10.1088/2041-8205/733/1/l3
accepted for publication by ApJ letters
arxiv created 2011/04/27 · openalex publication_date 2011/04/28 · arxiv updated 2015/05/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We observed asteroid (596) Scheila and its ejecta cloud using the Swift UV–optical telescope. We obtained photometry of the nucleus and the ejecta, and for the first time measured the asteroid's reflection spectrum between 290 and 500 nm. Our measurements indicate significant reddening at UV wavelengths (13% per 10 3 Å) and a possible broad, unidentified absorption feature around 380 nm. Our measurements indicate that the outburst has not permanently increased the asteroid's brightness. We did not detect any of the gases that are typically associated with either hypervolatile activity thought responsible for cometary outbursts (CO + , CO 2 + ), or for any volatiles excavated with the dust (OH, NH, CN, C 2 , C 3 ). We estimate that 6 × 10 8 kg of dust was released with a high ejection velocity of 57 m s −1 (assuming 1 μm sized particles). While the asteroid is red in color and the ejecta have the same color as the Sun, we suggest that the dust does not contain any ice. Based on our observations, we conclude that (596) Scheila was most likely impacted by another main belt asteroid less than 100 m in diameter.