Lost Asteroid

Lost Asteroid

Lost asteroids are asteroids that observers lose track of due to too short an observation arc to accurately predict the future location of the asteroid. Many early lost asteroids were rediscovered in the 1980s and 1990s, but a number of asteroids and other types of small Solar System bodies continue to be lost. By some definitions, about half of all discovered asteroids are lost – they cannot be found by pointing an appropriate telescope at their predicted location, because the uncertainty in their predicted orbit is too great or they are currently too faint to be detected.

Some asteroids and comets discovered in previous decades were "lost" because not enough observational data had been obtained to determine a reliable orbit. Without this information, astronomers would not know where to look for the object at future dates. Occasionally, a "newly discovered" object turns out to be a rediscovery of a previously lost object. This can be determined by calculating the "new" object's orbit backwards and checking its past positions against those previously recorded for the lost object. In the case of lost comets this is especially tricky because of nongravitational forces that can affect their orbits, such as emission of jets of gas from the comet nucleus. However, Brian G. Marsden has specialized in calculating such nongravitational forces. Notably, he successfully predicted the 1992 return of the once-lost periodic comet Swift–Tuttle.