For planetary systems, a retrograde movement usually means a movement that is opposite to rotating the main body, that is, the object that is the center of the system. Asteroids usually have a straight orbit around the sun. Currently, several dozen on retrograde orbits are known from the entire set of asteroids, which are most likely due to the gravitational interaction with Jupiter.
These objects include an asteroid of a doretse, which was discovered in 1999 in the observatory near the city of Sokorro (New Mexico, USA). It moves in orbit, which is characterized by a large eccentricity and, most importantly, retrograde movement. To allocate this fact, it was called a doretse: “asteroid” readable in the reverse order.
The asteroid circulation period around the Sun is 116 years away from 2.4 to 45.4 AE. According to these indicators of orbit, dorets are similar to the comet orbit that some researchers led to the assumption that the doretse has a cometic origin, since comets have a greater probability of being retrograde than asteroids. The famous comet Halley, for example, drawn by retrograde orbit around the sun.
In 2008, the first transneptune object with a retrograde orbit – 2008 KV42 was opened in the Mauna Kea Observatory. In the perihelion 2008 KV42, there is a little further orbit of uranium, at a distance of 20.3 AE. from the sun. During the opening, the object was at a distance of 32 AE. from the sun. Turnover around our shining Object 2008 KV42 makes approximately 300 years. An orbit inclination is 103 °. So unusual (retrograde) orbit made it possible to assume that 2008 KV42 moved to her from the Oort cloud.
Another transneptune object (471325) 2011 KT19, opened in 2011, attracted the attention of scientists due to the almost perpendicular retrograde movement of the object relative to other planets of the solar system. These circumstances prompted scientists to call the object Niku (Niku), which translated from Chinese means “unpumbed”.
Scientists have no reliable versions regarding non-standard behavior of these space wanders. Some researchers associate such anomalies with the gravitational effects of the hypothetical ninth planet, the search for which was not crowned with success. Anyway, a study of such objects must be continued, as they will help to identify areas that are sources of retrograde comet and asteroids, as well as understand the evolution of external regions of the solar system.
Source: Moscow Planetarium