Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. P/2010 A2 is a small Solar System body that displayed characteristics of both an asteroid and a comet, and thus, was initially given a cometary designation. Since it has the orbit of a main-belt asteroid and showed the tail of a comet, it was listed as a main-belt comet. But within a month of discovery, analysis of images by the Hubble telescope suggested that its tail was generated by dust and gravel resulting from a recent head-on collision between asteroids rather than from sublimation of cometary ice.