Asteroid 2020 JE2 passed by the Earth at a distance of about 844 600
km (2.20 times the average distance between the Earth and the Moon, or
0.56% of the distance between the Earth and the Sun), slightly before 7.20 pm
GMT on Monday 18 May 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 JE2 has an estimated
equivalent
diameter of 5-17 m (i.e. it is estimated that a spherical object
with
the same volume would be 5-17 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 40 and 25 km above the ground, with only fragmentary material
reaching the Earth's surface.
2020 JE2 was discovered on 15 May 2020 (three days before its closest encounter with the Earth) by the University of Hawaii's PANSTARRS telescope. The
designation 2020 JE2 implies that it was the 53rd asteroid (asteroid E2 -
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 E2 = (24 x 2) + 5 = 53)
discovered in the first half of May 2020 (period 2020 J - the
year being split into 24 half-months represented by the letters A-Y, with I being excluded).
2020 JE2 has an 541 day (1.48 year) orbital period and an eccentric orbit
tilted at an angle of 6.75° to the plane of the Solar System, which
takes it from 0.71 AU from the Sun (i.e. 71% of the the average distance at
which the Earth orbits the Sun, and slightly outside the orbit of Venus) to 1.88 AU from the Sun (i.e. 188% of
the
average distance at which the Earth orbits the Sun, more than the distance at which 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 close
encounters between the asteroid and Earth are fairly common, with the
last thought to have happened in May July 2017 and the next predicted
in May 2023. Asteroid 2020 JE2 also has regular close encounters with the planet Venus, which it last came close to in March 2013 and is next expected to approach in June this year (2020), and Mars, which it last came close to in October 1932.
Asteroids
which make close passes to multiple planets are considered to be in
unstable orbits, and are often eventually knocked out of these orbits by
these encounters, either being knocked onto a new, more stable orbit,
dropped into the Sun, knocked out of the Solar System or occasionally
colliding with a planet.
See also...
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