An asteroid pair, or (if more than two bodies) an asteroid cluster, are asteroids which at some point in the past had very small relative velocities, and are typically formed either by a collisional break-up of a parent body, or from binary asteroids which became gravitationally unbound and are now following similar but different orbits around the Sun.[1]

A possible example of a pair are the Trojan asteroids 1583 Antilochus and 3801 Thrasymedes. The proposer of that pair, Andrea Milani, found five other potential asteroid clusters in the Greek camp, clustered around the asteroids 1437 Diomedes, 1647 Menelaus, 2456 Palamedes, 2797 Teucer and 4035 Thestor.[2]

The youngest asteroid pairs discovered as of 2022 include the main-belt asteroids P/2016 J1-A/B (separated c. 2010) and (458271) 2010 UM26/2010 RN221 (separated c. 2003).[3][4] The former pair is particularly remarkable for exhibiting comet-like activity due to water ice sublimation and rotational break-up.[3]


  1. ^ Johnston, Wm. Robert (29 April 2018). "Asteroid pairs and clusters". Johnston's Archive. Retrieved 30 June 2018.
  2. ^ Milani, Andrea (October 1993). "The Trojan asteroid belt: Proper elements, stability, chaos and families". Celestial Mechanics and Dynamical Astronomy. 57 (1–2): 59–94. Bibcode:1993CeMDA..57...59M. doi:10.1007/BF00692462. ISSN 0923-2958. S2CID 189850747.
  3. ^ a b Moreno, F.; Pozuelos, F. J.; Novaković, B.; Licandro, J.; Cabrera-Lavers, A.; Bolin, B.; et al. (March 2017). "The Splitting of Double-component Active Asteroid P/2016 J1 (PANSTARRS)" (PDF). The Astrophysical Journal Letters. 837 (1): 6. arXiv:1702.03665. Bibcode:2017ApJ...837L...3M. doi:10.3847/2041-8213/aa6036. L3.
  4. ^ Vokrouhlický, D.; Fatka, P.; Micheli, M.; Pravec, P.; Christensen, E. J. (August 2022). "Extremely young asteroid pair (458271) 2010 UM26 and 2010 RN221" (PDF). Astronomy & Astrophysics. 664: 6. arXiv:2208.06207. Bibcode:2022A&A...664L..17V. doi:10.1051/0004-6361/202244589. L17.