List of unnumbered minor planets

The following is a list of unnumbered minor planets in chronological order of their principal provisional designation. Contrary to their numbered counterparts, unnumbered minor planets have a poorly determined orbit due to insufficient observational data. This also includes lost minor planets which have not been observed for many years, or even decades. The list below contains 194 objects with a principal designation assigned between 1927 and 1994. Additional partial lists cover the period from 1995 to 2004.[lower-alpha 1] Unnumbered minor planets detected after 2004 are not listed due to their large number (see statistics).

Breakdown of 936,303 small bodies of the Solar System:[1]   3,621 comets   545,135 numbered MPs   412,689 unnumbered MPs with a total of 957,824 minor planets (MPs)

As of April 2020, the JPL Small-Body Database gives a running total of 412,689 unnumbered minor planets, which represent 43.1% of the overall minor planet population of 957,824 bodies.[1] Based on its latest published data per 5 February 2020, the Minor Planet Center (MPC) accounts for 385,543 unnumbered minor planets, 545,135 numbered ones, and 4,149 comets.[2] Based on the latest published figures from May 2019, unnumbered minor planets were grouped by the MPC into 108,326 single-opposition objects with short observation arcs, prone to mismatch and loss, and 145,378 objects that have been observed multiple times during opposition, when astrometric conditions are most favorable.[3]

In the Minor Planet Circular from July 2018, the MPC announced that changes in their data processing pipeline will enable numberings to occur more frequently. It is stated that the new method will clear the backlog of unnumbered minor planets with an already well-established orbit without changing the criteria for numbering. Previously, this was not possible because of the difficulty of determining who was the discoverer.[4]