Aten
Aten, also Aton, Atonu, or Itn (, reconstructed ) was the focus of Atenism, the religious system formally established in ancient Egypt by the late Eighteenth Dynasty pharaoh Akhenaten. Exact dating for the Eighteenth Dynasty is contested, thou ...
asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
and
potentially hazardous object
A potentially hazardous object (PHO) is a near-Earth object – either an asteroid or a comet – with an orbit that can make close approaches to the Earth and which is large enough to cause significant regional damage in the event of impact. Th ...
. It has a well determined orbit with an observation arc of 7 years and an
uncertainty parameter
The uncertainty parameter ''U'' is introduced by the Minor Planet Center (MPC) to quantify the uncertainty of a perturbed orbital solution for a minor planet. The parameter is a logarithmic scale from 0 to 9 that measures the anticipated longitud ...
of 0. It was discovered on 1 April 2005 by the
Siding Spring Survey
The Siding Spring Survey (SSS) was a near-Earth object search program that used the 0.5-metre Uppsala Southern Schmidt Telescope at Siding Spring Observatory, New South Wales, Australia. It was the southern hemisphere counterpart of the Catalin ...
at an
apparent magnitude
Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...
of 18.1 using the
Uppsala Southern Schmidt Telescope
The Uppsala Schmidt Telescope is a Schmidt telescope located in Australia. It was moved to Siding Spring Observatory from Mount Stromlo Observatory in 1982. The instrument has been used to study galaxies, asteroids and comets. It was last dedi ...
.
Based on an absolute magnitude of 16.4, the asteroid has an estimated diameter of 1.6 km (within a factor of two). is the largest
potentially hazardous asteroid
A potentially hazardous object (PHO) is a near-Earth object – either an asteroid or a comet – with an orbit that can make close approaches to the Earth and which is large enough to cause significant regional damage in the event of impact. Th ...
(PHA) discovered in 2005. On 21 June 2012 it passed Earth at a distance of . The 2012 passage was studied with
radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
Arecibo
Arecibo (; ) is a Arecibo barrio-pueblo, city and Municipalities of Puerto Rico, municipality on the northern coast of Puerto Rico, on the shores of the Atlantic Ocean, located north of Utuado, Puerto Rico, Utuado and Ciales, Puerto Rico, Ciale ...