Asteroid 2020 HM6 passed by the Earth at a distance of about 162 900
km (0.42 times the average distance between the Earth and the Moon, 0.11% of the distance between the Earth and the Sun, or 399 times the distance at which the International Space Station orbots the Earth, and 4.55 times the distance of satellites in geostationary orbits), slightly after 5.50 am
GMT on Wednesday 22 April April 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 HM6 has an estimated
equivalent
diameter of 9-29 m (i.e. it is estimated that a spherical object
with
the same volume would be 9-29 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 32 and 17 km above the ground, with only fragmentary material
reaching the Earth's surface.
2020 HM6 was discovered on 24 April 2020 (two days after its closest encounter with 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 HM6
implies that the asteroid was the 156th object (asteroid M6 -
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, so that M6 = (24 x 6) + 12 = 156) discovered in the second half of April 2020 (period 2020 H).
2020 HM6 has a 1119 day (3.06 year) orbital period and an eccentric orbit
tilted at an angle of 2.29° to the plane of the Solar System, which
takes it from 0.76 AU from the Sun (i.e. 76% of he average distance at
which the Earth orbits the Sun) to 3.46 AU from the Sun (i.e. 346% of
the
average distance at which the Earth orbits the Sun, and more that twice the distance at which the planet Mars orbits the Sun). 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). This
means that 2020 HM6 has occassional close encounters with the Earth, with the next predicted
in May 2023.
See also...
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