Neptune Trojan - Members

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

Famous quotes containing the word members:

    “If the education and studies of children were suited to their inclinations and capacities, many would be made useful members of society that otherwise would make no figure in it.”
    —Samuel Richardson (1689–1761)

    “[T]here is no breaking out of the intentional vocabulary by explaining its members in other terms.”
    —Willard Van Orman Quine (b. 1908)

    “The English people believes itself to be free; it is gravely mistaken; it is free only during election of members of parliament; as soon as the members are elected, the people is enslaved; it is nothing. In the brief moment of its freedom, the English people makes such a use of that freedom that it deserves to lose it.”
    —Jean-Jacques Rousseau (1712–1778)