Aten asteroid
Encyclopedia
2062 Aten
2062 Aten is an asteroid that was discovered at the Palomar Mountain Observatory by Eleanor F. Helin, who is now the principal scientist for the NEAT project. It is named after Aten, the Egyptian god of the sun....
, discovered January 7, 1976, by Eleanor F. Helin
Eleanor F. Helin
Eleanor Francis "Glo" Helin was an American astronomer. She was principal investigator of the Near Earth Asteroid Tracking program of NASA's Jet Propulsion Laboratory. Some sources give her name as Eleanor Kay Helin...
). They are defined by having semi-major axes
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...
of less than one astronomical unit
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
(the distance from the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
). Note that, because asteroids' orbits can be highly eccentric, an Aten orbit need not be entirely contained within Earth's orbit; in fact, nearly all known Aten asteroids have their aphelion greater than one AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
.
Asteroids that have their aphelion entirely within the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's orbit are known as Apohele asteroid
Apohele asteroid
Apohele asteroids, or alternatively Interior-Earth Objects or Atira asteroids, are a subclass of Aten asteroids. They have not only their perihelion within Earth's orbit, but also their aphelion; that is, their entire orbit is within Earth's .The first suspected Apophele was , the first confirmed...
s, or alternatively as Inner Earth Objects (IEOs) or Atira asteroids. Apoheles are traditionally treated as a subclass of Atens, but sometimes are separated. As of June 2010, there are only ten known Apoheles, and 568 more known Aten asteroids. The smallest aphelion is that of ), at 0.804 AU. The shortest semi-major axis for any known Aten asteroid is that of another Apohele), at 0.550 AU.
The Aten asteroid with the smallest known perihelion is also the one with the highest known eccentricity: has an orbit with an eccentricity of 0.895, which takes it from a perihelion of 0.092 AU, well within Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
's orbit, to an aphelion of 1.661 AU.
For a brief time near the end of 2004, the asteroid 99942 Apophis
99942 Apophis
99942 Apophis is a near-Earth asteroid that caused a brief period of concern in December 2004 because initial observations indicated a small probability that it would strike the Earth in 2029. Additional observations provided improved predictions that eliminated the possibility of an impact on...
(then known only by its provisional designation ) appeared to pose a threat of causing an Earth impact event
Impact event
An impact event is the collision of a large meteorite, asteroid, comet, or other celestial object with the Earth or another planet. Throughout recorded history, hundreds of minor impact events have been reported, with some occurrences causing deaths, injuries, property damage or other significant...
in 2029, but earlier observations were found that eliminated that possibility, although a very small possibility remains for 2036.
See also
Aten asteroids (category)- List of numbered Aten asteroids
- Aten asteroid recordsAten asteroid recordsThe following is a list of current records for Aten asteroids.- External links :*...