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