The Arjuna asteroids (also known as "Arjunas") are a dynamical group of asteroids in the Solar System. Arjunas are near-Earth objects (NEOs) whose orbits are very Earth-like in character, having low inclination, orbital periods close to one year, and low eccentricity. The group is named after Arjuna, a central hero in Hindu epic Mahabharata. The definition is somewhat vague and overlaps the definition of the four well-established Apollo, Amor, Aten and Atira groups. They constitute a dynamically cold group of small NEOs that experience repeated trappings in the 1:1 mean-motion resonance with the Earth. [1] [2]
Potential members of the Arjuna group with their Apollo (APO) or Aten (ATE) group classification in parentheses, include:
2003 YN107 is a tiny asteroid, classified as a near-Earth object of the Aten group moving in a 1:1 mean-motion resonance with Earth. Because of that, it is in a co-orbital configuration relative to Earth.
Atira asteroids or Apohele asteroids, also known as interior-Earth objects (IEOs), are Near-Earth objects whose orbits are entirely confined within Earth's orbit; that is, their orbit has an aphelion smaller than Earth's perihelion, which is 0.983 astronomical units (AU). Atira asteroids are by far the least numerous group of near-Earth objects, compared to the more populous Aten, Apollo and Amor asteroids.
A quasi-satellite is an object in a specific type of co-orbital configuration with a planet where the object stays close to that planet over many orbital periods.
524522 Zoozve (provisional designation 2002 VE68) is a sub-kilometer sized asteroid and temporary quasi-moon of Venus. Discovered in 2002, it was the first such object to be discovered around a major planet in the Solar System. It has nearly the same orbital period around the Sun that Venus does. In a frame of reference rotating with Venus, it appears to travel around it during one Venerean year, but it orbits the Sun, not Venus.
Mount Lemmon Survey (MLS) is a part of the Catalina Sky Survey with observatory code G96. MLS uses a 1.52 m (60 in) cassegrain reflector telescope operated by the Steward Observatory at Mount Lemmon Observatory, which is located at 2,791 meters (9,157 ft) in the Santa Catalina Mountains northeast of Tucson, Arizona.
The Mars trojans are a group of trojan objects that share the orbit of the planet Mars around the Sun. They can be found around the two Lagrangian points 60° ahead of and behind Mars. The origin of the Mars trojans is not well understood. One theory suggests that they were primordial objects left over from the formation of Mars that were captured in its Lagrangian points as the Solar System was forming. However, spectral studies of the Mars trojans indicate this may not be the case. Another explanation involves asteroids chaotically wandering into the Mars Lagrangian points later in the Solar System's formation. This is also questionable considering the short dynamical lifetimes of these objects. The spectra of Eureka and two other Mars trojans indicates an olivine-rich composition. Since olivine-rich objects are rare in the asteroid belt it has been suggested that some of the Mars trojans are captured debris from a large orbit-altering impact on Mars when it encountered a planetary embryo.
2012 XE133 is an asteroid, classified as near-Earth object of the Aten group that is a temporary co-orbital of Venus.
2013 BS45 (also written 2013 BS45) is a horseshoe companion to the Earth like 3753 Cruithne. Like Cruithne, it does not orbit the Earth in the normal sense and at times it is on the other side of the Sun, yet it still periodically comes nearer to the Earth in sort of halo orbit before again drifting away. While not a traditional natural satellite, it does not quite have normal heliocentric orbit either and these are sometimes called quasi-satellties or horseshoe orbits.
2006 JY26 is a near-Earth object that is also horseshoe companion to the Earth like 3753 Cruithne.
2012 FC71, also written 2012 FC71, is a small asteroid trapped in a Kozai resonance with the Earth.
2013 ND15 (also written 2013 ND15) is an asteroid that is a temporary trojan of Venus, the first known Venus trojan.
2014 OL339 (also written 2014 OL339) is an Aten asteroid that is a temporary quasi-satellite of Earth, the fourth known Earth quasi-satellite.
2015 SO2 (also written 2015 SO2) is an Aten asteroid that is a temporary horseshoe companion to the Earth, the ninth known Earth horseshoe librator. Prior to its most recent close encounter with our planet (2015 September 30) it was an Apollo asteroid.
2015 YA is a sub-kilometer asteroid, classified as near-Earth object of the Aten group, that is a temporary horseshoe companion to the Earth. It is the 11th known Earth horseshoe librator. Prior to a close encounter with the Earth on 15 December 2015, 2015 YA was an Apollo asteroid.
2017 DR109, is a micro-asteroid, classified as near-Earth object of the Apollo group and Aten group, respectively. It is currently trapped in a 1:1 mean motion resonance with the Earth of the horseshoe type. The object was first observed on 27 February 2017, by astronomers of the Catalina Sky Survey conducted at Mount Lemmon Observatory, Arizona, United States.
2009 SE is a small asteroid and Mars trojan orbiting near the L5 point of Mars (60 degrees behind Mars on its orbit).
2018 FC4 is a small asteroid and Mars trojan orbiting near the L5 point of Mars (60 degrees behind Mars on its orbit).
2020 PN1 is a sub-kilometer asteroid, classified as a near-Earth object of the Aten group, that is a temporary horseshoe companion to the Earth. There are dozens of known Earth horseshoe librators, some of which switch periodically between the quasi-satellite and the horseshoe co-orbital states.
2009 SH2 is a sub-kilometer near-Earth asteroid of the Aten group, discovered by the Siding Spring Survey at Siding Spring Observatory, Australia on 18 September 2009. It is in a co-orbital configuration with Earth, a type of 1:1 orbital resonance where the asteroid appears to librate around Earth's path in a horseshoe orbit when viewed in a corotating reference frame with Earth. The co-orbital state of 2009 SH2 is only temporary as it has entered it about 30 years ago and will leave it in about 100 years into the future.