Neptune Trojan

asteroid orbiting the Sun near one of the stable Lagrangian points of Neptune

A Neptune Trojan is an asteroid which is in the same orbit as the planet Neptune.

Their name comes from the Trojan asteroids which have the same orbital period as a planet. As of March 2007, there are six[1][2] known Neptune Trojans. They lie in the elongated, curved region around the L4 Lagrangian point 60° ahead of Neptune. The six Neptune Trojans are 2001 QR322, 385571 Otrera, 2005 TN53, 385695 Clete, 2006 RJ103 and 2007 RW10.

The discovery of 2005 TN53 in a high inclination (>25°) orbit is significant because it suggests a ‘thick’ cloud of Trojans.[3] It is believed that large (radius ≈ 100 km) Neptune Trojans could greatly outnumber the Jupiter Trojans.[4][5]

The New Horizons spacecraft passed through the L5 Neptune region in 2014. It was preparing to observe Pluto and did not observe any asteroids there.

References change

  1. 2005 TN74, listed earlier as a Neptune Trojan, proved to be a scattered disk object.
  2. List Of Neptune Trojans (March 8, 2007) at
  3. S. Sheppard and C. Trujillo "A Thick Cloud of Neptune Trojans and Their Colors" (2006) Science 313, pp. 511-514
  4. E. I. Chiang and Y. Lithwick Neptune Trojans as a Testbed for Planet Formation, The Astrophysical Journal, 628, pp. 520–532 Preprint
  5. popular article (Jan 2007)