Unusual minor planet


In planetary science, the term unusual minor planet, or unusual object, is used for a minor planet that possesses an unusual physical or orbital characteristic. For the Minor Planet Center, which operates under the auspices of the International Astronomical Union, any non-classical main-belt asteroid, which account for the vast majority of all minor planets, is an unusual minor planet. These include the near-Earth objects and Trojans as well as the distant minor planets such as centaurs and trans-Neptunian objects. In a narrower sense, the term is used for a group of bodies – including main-belt asteroids, Mars-crossers, centaurs and otherwise non-classifiable minor planets – that show a high orbital eccentricity, typically above 0.5 and/or a perihelion of less than 6 AU. Similarly, an unusual asteroid is an inner Solar System object with a high eccentricity and/or inclination but with a perihelion larger than 1.3 AU, which does exclude the near-Earth objects.

Other unusual objects

The MPC lists the group of other unusual minor planets, which orbital characteristics do not fit those of the near-Earth and distant populations. Objects in this group typically have a TJupiter of less than 3. The remaining unusual objects with a TJupiter higher than 3 are Mars-crossing asteroids with a high eccentricity of 0.5 or more. As of 2019, there are 830 unusual objects in total, most of which remain unnumbered. The following list also includes a few named bodies: