INTERPRETATION OF (596) SCHEILA'S TRIPLE DUST TAILS

Abstract

Strange-looking dust cloud around asteroid (596) Scheila was discovered on\n2010 December 11.44-11.47. Unlike normal cometary tails, it consisted of three\ntails and faded within two months. We constructed a model to reproduce the\nmorphology of the dust cloud based on the laboratory measurement of high\nvelocity impacts and the dust dynamics. As the result, we succeeded in the\nreproduction of peculiar dust cloud by an impact-driven ejecta plume consisting\nof an impact cone and downrange plume. Assuming an impact angle of 45 deg, our\nmodel suggests that a decameter-sized asteroid collided with (596) Scheila from\nthe direction of (alpha, delta) = (60deg, -40deg) in J2000 coordinates on 2010\nDecember 3. The maximum ejection velocity of the dust particles exceeded 100\nm/s. Our results suggest that the surface of (596) Scheila consists of\nmaterials with low tensile strength.\n