The known Neptune Trojans are estimated to have diameters of 60 to 140 km. From a statistical analysis based on the 25° tilt of 2005 TN53's orbit, researchers have inferred that Neptune may have between five and 20 times more of these large objects than Jupiter does. Jupiter has only one known Trojan in this upper size range. Based on this difference, astronomers estimate that Neptune's smaller Trojans also outnumber Jupiter's. Other research implies that Jupiter may have about the same number of asteroids as the main asteroid belt, so astronomers indirectly conclude that Neptune Trojans may outnumber the tens of thousands of asteroids in the main asteroid belt. However, because Neptune is farther away, spotting these rocky objects is difficult. A cloud of asteroids at the L5 point, 60° behind Neptune, has not yet been seen but is predicted to exist. One reason why no L5 Neptune Trojans have yet been discovered is that, given the present location of Neptune relative to Earth its L5 point lies in the same direction as a dense backdrop of stars in the Milky Way, which makes spotting faint asteroids difficult. However, planetary motions will make for a better view of any trailing Trojans in about 30 years.
Related category ASTEROIDS AND OTHER MINOR PLANETS: TYPES AND GROUPS
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