Critical-list minor planet
A critical-list minor planet is a numbered minor planet whose orbit and position measurements need significant improvement. The Minor Planet Center (MPC) regularly publishes a list of these objects in its Minor Planet Electronic Circulars. The list usually includes asteroids that have been observed only a few times (often at opposition) or haven’t been tracked well for more than 10 years. Other observatories also create their own critical-object lists.
The MPC also shows currently observable critical objects on its website, in several formats of orbital data for the astronomy community worldwide.
Lowell Observatory runs its own critical list, which is different from the MPC’s. It focuses on objects with high uncertainty in their predicted positions. Specifically, it includes objects whose computed ephemeris uncertainty exceeds 2 arcseconds over the next 10 years, or objects whose orbits would degrade significantly if some past observations were ignored.
As of December 2024, the MPC lists 650 observable critical objects.
The list below includes all critical objects among the first 100,000 numbered minor planets; the full list is available on the MPL website.
This page was last edited on 3 February 2026, at 18:02 (CET).