|- style="vertical-align: top;"| Galactic coordinates | 260.3841 −03.4718
RX J0822−4300, often referred to as a "Cosmic Cannonball", is a radio-quiet neutron star currently moving away from the center of the Puppis A supernova remnant at, making it one of the fastest moving stars ever found.[1] Earlier, it was believed to move with speed as high as 1,500 km/s. Astronomers used NASA's Chandra X-ray Observatory to observe the star over a period of 11 years to determine its speed.[1]
Although the cosmic cannonball is not the only hypervelocity star discovered, it is unique in the apparent origin of its speed. Others may have derived theirs from a gravitational slingshot around the Milky Way's suspected supermassive black hole, Sagittarius A*. Current theories fail to explain how such speeds can be attained from a supernova explosion. It could be a possible quark star.