A critical-list minor planet (critical list numbered object or critical object) is a numbered minor planet whose orbit and position is especially in need of improvement. The IAU's Minor Planet Center (MPC) regularly publishes a list of these critical objects in their Minor Planet Electronic Circular. The list typically contains asteroids that have been observed at a small number of apparitions, especially on opposition, or that have not been adequately observed for more than 10 years, while other observatories create their own, customized lists. The MPC also lists currently observable critical objects on their website, providing differently formatted lists of orbital elements to the worldwide astrometric community. , the MPC includes more than a thousand objects in their critical list, half of them being either near-Earth asteroids or distant minor planets which account for 674 and 192 critical objects, respectively. List The lowest numbered critical-list objects are: 1915 Quetzálcoatl 2135 Aristaeus 3362 Khufu 3753 Cruithne (4688) 1980 WF 5335 Damocles (5590) 1990 VA 7066 Nessus (8014) 1990 MF 10370 Hylonome 14827 Hypnos (15789) 1993 SC (15809) 1994 JS 19521 Chaos 20461 Dioretsa See also Distant minor planet Lost minor planet Unusual minor planet References External links MPEC 1998-G21 : CRITICAL-LIST MINOR PLANETS, Minor Planet Circular (1998) Asteroid orbit determination using Bayesian probabilities, Karri Muinonen, Edward Bowell (1993) Minor planets