Asteroid 2020 OW5 passed by the Earth at a distance of about 924 500
km (2.41 times the average distance between the Earth and the Moon, or
0.62% of the distance between the Earth and the Sun), slightly after 6.05 pm
GMT on Tuesday 25 July 2020. There was no danger of
the asteroid hitting us, though were it to do so it would not have
presented a significant threat. 2020 OW5 has an estimated
equivalent
diameter of 11-35 m (i.e. it is estimated that a spherical object
with
the same volume would be 11-35 m in diameter), and an object of this
size
would be expected to explode in
an airburst (an explosion caused by superheating from friction with the
Earth's atmosphere, which is greater than that caused by simply
falling, due to the orbital momentum of the asteroid) in the atmosphere
between 30 and 15 km above the ground, with only fragmentary material
reaching the Earth's surface.
The orbit and current position of 2020 OW5. The Sky Live 3D Solar System Simulator.
2020 OW5 was discovered on 29 Juy 2020 (four days after its closest approach to the Earth) by the
University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount
Lemmon in the Catalina Mountains north of Tucson. The designation 2020 OW
implies that the asteroid was the 142nd object (asteroid W5 -
in numbering asteroids the letters A-Y, excluding I, are assigned
numbers from 1 to 24, with a number added to the end each time the
alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that W5 = (24 x 5) + 22 = 142) discovered in the second half of July 2020 (period 2020 O).
2020 OW5 has a 963 day (2.64 year) orbital period, with an elliptical
orbit tilted at
an angle of 0.85° to the plain of the Solar System which takes in to 1.00 AU from the Sun (the distance at which the Earth orbits the
Sun) and out to 2.82 AU (2.82% of the distance at which the Earth orbits
the sun and almost twice as far from the Sun as the planet Mars). It is therefore classed as
an Apollo Group Asteroid (an asteroid that is on average further from the Sun
than the Earth, but which does get closer). 2020 OW5 has had one previous close encounter with the Earth, in September 1991.
See also...
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