2013/06/17 by David Jewitt, Jing Li, Jessica Agarwal · 1 citation
Physics and Astronomy · #astro-ph.EP
paper · pdf · doi:10.1088/2041-8205/771/2/l36
13 pages, 4 figures. Accepted by ApJL
arxiv created 2013/06/17 · arxiv updated 2015/06/16
We report the discovery of a comet-like tail on asteroid (3200) Phaethon when imaged at optical wavelengths near perihelion. In both 2009 and 2012, the tail appears >=350" (2.5x108 m) in length and extends approximately in the projected anti-solar direction. We interpret the tail as being caused by dust particles accelerated by solar radiation pressure. The sudden appearance and the morphology of the tail indicate that the dust particles are small, with an effective radius ~1 micrometer and a combined mass ~3x105 kg. These particles are likely products of thermal fracture and/or desiccation cracking under the very high surface temperatures (~1000 K) experienced by Phaethon at perihelion. The existence of the tail confirms earlier inferences about activity in this body based on the detection of anomalous brightening. Phaethon, the presumed source of the Geminid meteoroids, is still active.