Asteroid 2019 KG2 passed by the Earth at a distance of about 1 017 000
km (2.65 times the average distance between the Earth and the Moon, or
0.68% of the distance between the Earth and the Sun), at about 3.10 pm
GMT on Thursday 30 May 2019. There was no danger of
the asteroid hitting us, though were it to do so it would not have
presented a significant threat. 2019 KG2 has an estimated
equivalent
diameter of 12-39 m (i.e. it is estimated that a spherical object
with
the same volume would be 12-39 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 10 km above the ground, with only fragmentary material
reaching the Earth's surface.
The calculated orbit of 2019 KG2. Minor Planet Center.
2019 KG2 was discovered on 27 May 2019 (three days before 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 2019 KG2
implies that the asteroid was the 55th object (object G2 - in numbering asteroids the letters A-Y, excluding I, are assigned
numbers from 1 to 24, so that G2 = (24 x 2) + 7 = 55) discovered in the second half of May 2019 (period 2019 K).
2019 KG2 has an 374 day orbital period and an eccentric orbit
tilted at an angle of 19.7° to the plane of the Solar System, which
takes it from 0.79 AU from the Sun (i.e. 79% of the the average distance
at
which the Earth orbits the Sun) to 1.24 AU from the Sun (i.e. 124% of
the
average distance at which the Earth 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 close
encounters between the asteroid and Earth are very common, with the
last having occurred in May 2018 and the next predicted
in June 2020.
See also...
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