• Processing (Info)

  • How Are Minor Planets Named?

    The quick version: the discoverer of a particular object has the privilege of suggesting a name to a committee that judges its suitability. Contrary to some recent media reports it is not possible to buy a minor planet. If you have a name you would like to apply, the best advice is "Go out and discover one!". Information on how this might be achieved is available.


    A fuller description of how minor planets are named is given below, but you will need to understand some basic astronomical concepts in order to fully appreciate it.

    1. The assignment of a particular name to a particular minor planet is the end of a long process that can take many decades.

    2. It begins with the discovery of a minor planet that cannot be identified with any already-known multiple-opposition or recent single-opposition object. When observations on two nights of a new object have been reported to the Minor Planet Center, a new provisional designation is assigned to the object. These two nights do not need to come from the same observer.

      • At this stage, it is possible to search for identifications with previously-discovered provisionally-designated objects observed at only one opposition in the past. If an identification is made, one of the provisional designations is chosen by the identifier as the principal designation. The selection of which designation is chosen has no effect on who will be the discoverer when the object is numbered.

      • If no identifications are forthcoming, further observations of the new object are obtained and an orbit is computed. The object is followed for as long as possible at the discovery opposition (some objects are followed for three or four months). Additional searches for identifications can be made as each new set of observations is obtained. If any identifications are made one of the designations involved is chosen as the principal designation.

      • If no identifications are found and the observed arc reaches two or three months, it is likely that the object may be found as a result of a direct search at the next opposition.

    3. Further observations are made of the object at later oppositions. When there are observations at four or more oppositions the object may receive a permanent designation, a number. (The actual circumstances under which objects are numbered are rather complex and subject to occasional revision, but four well-observed oppositions will usually suffice.) For unusual objects, such as NEAs (Near-Earth Asteroids), numbering might occur after three, maybe even only two, oppositions.
      • The discoverer of the numbered object is defined in one of two ways:
        • For objects that had multiple-opposition orbits prior to the issuance of MPEC 2010-U20, the discover of the numbered object is the same as the discoverer of the principal designation.
        • For objects that became multi-opposition after that MPEC, the discoverer of the numbered object is the observer who made the earliest-reported observation at the opposition with the earliest-reported second-night observation.

      • This discoverer is accorded the privilege of suggesting a name for his/her discovery. The discoverer has the privilege for a period of ten years following the numbering of the object.

      • The discoverer writes a short citation explaining the reasons for assigning the name.

    4. Names are judged by the fifteen-person Committee for Small-Body Nomenclature (formerly the Small Bodies Names Committee) of the International Astronomical Union, comprised of professional astronomers (with research interests connected with minor planets and/or comets) from around the world.
      • Proposed names should be:
        • 16 characters or less in length (including any spaces or punctuation)
        • preferably one word
        • pronounceable (in some language)
        • non-offensive
        • not too similar to an existing name of a minor planet or natural planetary satellite

      • Names for persons or events known primarily for their military or political activities are acceptable only after 100 years elapsed since the person died or the event occurred.

      • Names of pet animals are discouraged.

      • Names of a purely or principally commerical nature are not allowed.

    5. Certain classes of names are to be applied to specific orbital classes of minor planets.
      • Objects in the classical TNO belt are to receive names of creation deities.
      • Objects in orbits in 3:2 resonance with Neptune are to receive names of underworld deities.
      • Objects in orbits between the orbits of Jupiter and Neptune, and not in 1:1 resonance with any major planet, are to receive names of centaurs.
      • Objects in 1:1 resonance with Jupiter are to receive names associated with the Trojan War. Objects at the preceding L4 point are named for Greeks, objects at the trailing L5 point are named for Trojans.
      • Near-Earth Objects are to receive names from mythology, except names associated with creation or underworld themes.

    6. Accepted names become official when they are published, along with their accompanying citations, in the Minor Planet Circulars, issued monthly by the Minor Planet Center (an official service of IAU Commission 20).


    An alphabetical list of minor-planet names is available.