Members
The amount of high-inclination objects in such a small sample, in which relatively fewer high-inclination Neptune trojans are known due to observational biases, implies that high-inclination trojans may significantly outnumber low-inclination trojans. The ratio of high- to low-inclination Neptune trojans is estimated to be about 4:1. Assuming albedos of 0.05, there are an expected 400+250
−200 Neptune trojans with radii above 40 km in Neptune's L4. This would indicate that large Neptune trojans are 5 to 20 times more abundant than Jupiter Trojans, depending on their albedos. There may be relatively fewer smaller Neptune trojans, which could be because these fragment more readily. Large L5 trojans are estimated to be as common as large L4 trojans.
2001 QR322 displays significant dynamical instability. This means it could have been captured after planetary migration, but may as well be a long-term member that happens not to be perfectly dynamically stable.
As of October 2012, nine Neptune trojans are known, of which six orbit near the Sun–Neptune L4 Lagrangian point 60° ahead of Neptune and three orbit near Neptune's L5 region 60° behind Neptune. These are listed in the following table. It is constructed from information obtained from the List Of Neptune Trojans maintained by the IAU Minor Planet Center and with diameters from Sheppard and Trujillo's paper on 2008 LC18, unless otherwise noted.
| Provisional Designation |
Lagrangian Point |
Perihelion (AU) |
Aphelion (AU) |
Inclination (°) |
Absolute magnitude |
Diameter (km) |
Year of identification |
Reference |
|---|---|---|---|---|---|---|---|---|
| 2001 QR322 | L4 | 29.428 | 31.349 | 1.3 | 8.2 | ~140 | 2001 | |
| 2004 UP10 | L4 | 29.351 | 31.259 | 1.4 | 8.8 | ~100 | 2004 | |
| 2005 TN53 | L4 | 28.253 | 32.284 | 25.0 | 9.1 | ~80 | 2005 | |
| 2005 TO74 | L4 | 28.733 | 31.824 | 5.2 | 8.5 | ~100 | 2005 | |
| 2006 RJ103 | L4 | 29.345 | 31.005 | 8.2 | 7.5 | ~180 | 2006 | |
| 2007 VL305 | L4 | 28.131 | 32.171 | 28.1 | 8.0 | ~160 | 2007 | |
| 2008 LC18 | L5 | 27.547 | 32.468 | 27.5 | 8.4 | ~100 | 2008 | |
| 2004 KV18 | L5 | 24.566 | 35.657 | 13.6 | 8.9 | 56 | 2011 | |
| 2011 HM102 | L5 | 27.691 | 32.409 | 29.4 | 8.1 | 90–180 | 2012 |
2005 TN74 and (309239) 2007 RW10 were believed to be Neptune trojans at the time of their discovery, but further observations have disconfirmed their membership. 2005 TN74 is currently thought to be in a 3:5 resonance with Neptune. (309239) 2007 RW10 is currently following a quasi-satellite loop around Neptune.
Read more about this topic: Neptune Trojan
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