Astrophysics (index)

Provisional Designation

(way to designate newly discovered solar system objects)

Astronomy has Provisional Designation systems to label objects that have just been discovered. Distant objects can be immediately labeled by their position on the Celestial Sphere, but for newly-discovered solar system objects (minor planets), a system independent of position is necessary. A Survey-based Designator is often used, but a general system has also been adopted that uses the date and order of discovery.

DDDD AAnumber
  • DDDD - four-digit year.
  • AA - 2 letters, skipping the letter "I". The first letter indicates the half-month, days 1-15 being the first half (i.e., A for January 1-15, B for January 16-31, etc.), the second letter indicating the order of discovery, A for the first, B for the second, etc.
  • number: if more than 25 objects are discovered, a 2 or higher integer indicates the 2nd letter has begun again at "A". E.g., the 26th object is given an A subscripted by a 2, the 27th, a B2, etc.

Example: 2016 EK156

  • 2016 - year of discovery.
  • E - discovered within March 1-15.
  • K156 - 3910th object discovered in that period, i.e., K for 10th discovery after 25 × 156 previous discoveries.

(astronomy,designation,solar system)

Referenced by:
101955 Bennu
New Horizons