The Damocloid are a group of unusual asteroids that are inactive nuclei of Halley’s Comet and other long-period comets, and have been found to have a retrograde orbit, unlike other types of asteroids. Its name was derived from its archetype, the 5335 Damocles that was discovered by Robert McNaught in 1991. Robert McNaught named his discovery after Damocles, who is a character in the Greek mythology. The Damocloid has similar characteristics to comets and are sometimes indistinguishable from them. In fact, a Damocloid can develop tails making them, technically, a comet. These asteroids were rendered inactive after they lost their volatile material due to out gassing, which is the slow release of adsorbed gas.
The albedos or the strength in which an object reflects light from the sun, of Damocloid was measured and it was found that these asteroids have a reddish color; however, their red hue is less intense as that of Centaurs and many Kuiper belt objects. On average, their radius is about eight kilometers. There are about twenty-five known Damocloid, as of 2005. As previously mentioned, a Damocloid is difficult to identify and in fact, about four asteroids that were named Damocloid turned out to be false. These were the C/2001 OG108 (LONEOS), C/2002 CE10 (LINEAR), C/2002 VQ94 (LINEAR), C/2004 HV60 (Spacewatch). These asteroids were later identified as comets.