2002 AA29 is a small near-Earth asteroid that was discovered on January 9,2002 by the LINEAR automatic sky survey. The diameter of the asteroid is only about 20–100 metres and it revolves about the Sun on an almost circular orbit very similar to that of the Earth. This lies for the most part inside the Earths orbit, which it crosses near the asteroids furthest point from the Sun, because of this orbit, the asteroid is classified as Aten type, named after the asteroid Aten. A further characteristic is that its mean orbital period about the Sun is exactly one sidereal year and this means that it is locked into a relationship with the Earth, since such an orbit is only stable under particular conditions. As yet only a few asteroids of this sort are known, the first was Cruithne, discovered in 1986. Asteroids that have a 1,1 orbital resonance with a planet are called co-orbital objects, the most numerous known co-orbital asteroids are the so-called trojans, which occupy the L4 and L5 Lagrangian points of the relevant planet.
However,2002 AA29 does not belong to these, instead, it follows a so-called horseshoe orbit along the path of the Earth. The orbits of most asteroids lie in the belt between Mars and Jupiter. 2002 AA29 has probably been brought in the way from the outer Solar System into Earth’s influence. However, it is suggested that the asteroid has always been on a near-Earth orbit. In this case one possibility is that it could be a fragment from a collision of an asteroid with Earth or the Moon. Its mean orbital period is one sidereal year, after it was diverted into the inner Solar System – or formed on a path near Earth’s orbit – the asteroid must have been moved into an orbit corresponding with Earth. In this orbit it was pulled by Earth in such a way that its own orbital period became the same as that of Earth. In the current orbit, Earth thus holds the asteroid in synchronicity with its own orbit, the orbit of the asteroid is almost circular, with an eccentricity of 0.012 which is even lower than that of the Earth at 0.0167.
The other near-Earth asteroids have on average a higher eccentricity of 0.29. Also, all other asteroids in 1,1 resonance with Earth known before 2002 have very elliptical orbits – e. g. the eccentricity of Cruithne is 0.515. The orbital inclination with respect to the ecliptic of 2002 AA29 is a moderate 10. 739°, hence its orbit is slightly tilted compared with that of Earth, if it were not tilted at all, the orbits would lie right on top of each other. The shape of this arc is reminiscent of a horseshoe, from which comes the name “horseshoe orbit”, as it moves along the Earths orbit, it winds in a spiral about it, in which each loop of the spiral takes one year
2000 EM26 is a near-Earth and potentially hazardous asteroid. It was discovered on 5 March 2000 and observed through 14 March 2000 by which time it had dimmed to apparent magnitude 20 and was 40 degrees from the moon, by 17 March 2000 it was only 4 degrees from a 90% waxing gibbous moon. It has never listed on the Sentry Risk Table because none of the potential orbital solutions create a risk of impact in the next ~100 years. The asteroid is up to 270 meters in diameter and safely passed by Earth on 17–18 February 2014, due to the poorly determined orbit, the asteroid may have been significantly further from Earth and dozens of degrees from where the telescope was pointed during the 2014 approach. The 2014 approach was broadcast live on the internet at 09, 00pm EST,18 February 2014, sloohs observatory on Mount Teide in Spains Canary Islands was iced over at the time, so images from the Slooh observatory in Dubai were used to attempt detection of the asteroid. At the time of the broadcast, no image of the asteroid could be seen.
Some viewers complained by Twitter that it was boring when the object was never shown in the images,2000 EM26 is an Aten-family asteroid, and as such is often near the glare of the Sun as the asteroid seldom travels outside Earths orbit when the Earth is nearby. The orbit is poorly determined since the asteroid has an arc of only 9 days creating an orbital uncertainty of 7. Since the asteroid has not been observed since 14 March 2000, during the 2014 approach,17 February 2014 was the first day that the nominal orbit had a solar elongation more than 90 degrees from the Sun making it easier to recover under a dark sky. Using the nominal orbit, the asteroid was expected to have an apparent magnitude of about 16, closest approach was around 00,15 UTC on 18 February plus or minus about 13 hours. Due to the uncertainty region of the asteroid, the asteroid could have been 75 degrees from the position in the sky on 18 February 2014. With an absolute magnitude of 21.7, the asteroid is estimated as around 120–270 m in diameter, depending on the albedo.
List of asteroid close approaches to Earth 2009 RR2000 EM26 at Solar System Dynamics/NASA2000 EM26 at the JPL Small-Body Database Discovery · Orbit diagram · Orbital elements · Physical parameters
1998 KY26 is a small near-Earth asteroid. It was discovered on June 2,1998, by Spacewatch and observed until June 8 and it is roughly spherical and is only about 30 metres in diameter. With a rotation period of 10.7 minutes it has one of the shortest sidereal days of any object in the Solar System. It is one of the most easily accessible objects in the Solar System and this, coupled with the fact that it is water rich, makes it an attractive target for further study and a potential source of water for future missions to Mars. It was the first recognized minor object that spins so fast that it must be an object rather than a rubble pile. Since 1998 KY26 was found to be a fast rotator, several other small asteroids have been found to have short rotation periods and radar observations indicate that 1998 KY26 is a water-rich object. These physical properties were measured by a team of astronomers led by Dr. Steven J. Ostro of the Jet Propulsion Laboratory. The team used a telescope in California and optical telescopes in the Czech Republic, Arizona.
Radar and Optical Observations of Asteroid 1998 KY26, tholen, D. J. Recovery of 1998 KY26, Implications for Detecting the Yarkovsky Effect. Bulletin of the American Astronomical Society, archived from the original on 2009-10-22. Sun never sets, for long, on fast-spinning, water-rich asteroid
1999 CW8 is an Apollo asteroid and near-Earth object that is a B-type asteroid, relatively rare in the asteroid belt but common in the inner solar system. The asteroid never approaches Earth closer than 0.2 AU and it makes one such approach in 2073, at 0.067 AU, and another one in 2103, at 0.094 AU. Due to 1999 CW8s relatively high inclination, although it passes closer to the Sun than the Earth, based on absolute magnitude, and assuming an albedo between 0.05 and 0. However, it is unlikely to come close enough to Earth to impact it, mars-crossing asteroid 1999 CW8 at the JPL Small-Body Database Discovery · Orbit diagram · Orbital elements · Physical parameters
1999 LE31 is a damocloid centaur discovered on June 12,1999. It is both a Jupiter and Saturn-crossing minor planet, due to this, it must have originated from elsewhere, most likely outside Neptune. Of over half a million known minor planets,1999 LE31 is one of about 60 that has a retrograde orbit,1999 LE31 is approximately 16.8 km in diameter. It came to perihelion in December 1998 and it was last observed in 2000, and will next come to perihelion in February 2022. k. a. 1999 LD312000 DG8 List of notable asteroids Interactive orbit diagram Yanga R. Fernández, David C
A minor planet is an astronomical object in direct orbit around the Sun that is neither a planet nor exclusively classified as a comet. Minor planets can be dwarf planets, trojans, Kuiper belt objects, as of 2016, the orbits of 709,706 minor planets were archived at the Minor Planet Center,469,275 of which had received permanent numbers. The first minor planet to be discovered was Ceres in 1801, the term minor planet has been used since the 19th century to describe these objects. The term planetoid has used, especially for larger objects such as those the International Astronomical Union has called dwarf planets since 2006. Historically, the asteroid, minor planet, and planetoid have been more or less synonymous. This terminology has become complicated by the discovery of numerous minor planets beyond the orbit of Jupiter. A Minor planet seen releasing gas may be classified as a comet. Before 2006, the IAU had officially used the term minor planet, during its 2006 meeting, the IAU reclassified minor planets and comets into dwarf planets and small Solar System bodies.
Objects are called dwarf planets if their self-gravity is sufficient to achieve hydrostatic equilibrium, all other minor planets and comets are called small Solar System bodies. The IAU stated that the minor planet may still be used. However, for purposes of numbering and naming, the distinction between minor planet and comet is still used. Hundreds of thousands of planets have been discovered within the Solar System. The Minor Planet Center has documented over 167 million observations and 729,626 minor planets, of these,20,570 have official names. As of March 2017, the lowest-numbered unnamed minor planet is 1974 FV1, as of March 2017, the highest-numbered named minor planet is 458063 Gustavomuler. There are various broad minor-planet populations, traditionally, most have been bodies in the inner Solar System. Near-Earth asteroids, those whose orbits take them inside the orbit of Mars. Further subclassification of these, based on distance, is used, Apohele asteroids orbit inside of Earths perihelion distance.
Aten asteroids, those that have semi-major axes of less than Earths, Apollo asteroids are those asteroids with a semimajor axis greater than Earths, while having a perihelion distance of 1.017 AU or less. Like Aten asteroids, Apollo asteroids are Earth-crossers, amor asteroids are those near-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it