Asteroid 2020 CG2 passed by the Earth at a distance of about 863 600
km (2.25 times the average distance between the Earth and the Moon, or
0.58% of the distance between the Earth and the Sun), slightly before 8.20 am
GMT on Monday 17 February 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 CG2 has an estimated
equivalent
diameter of 25-78 m (i.e. it is estimated that a spherical object
with
the same volume would be 25-78 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 24 and 3 km above the ground, with only fragmentary material
reaching the Earth's surface.
240 second image of 2020 CG2 taken with the Elena Planetwave 17" Telescope at Ceccano
in Italy on 16 February 2020. The asteroid is the small point at the
centre of the image, the longer lines are stars, their elongation being
caused by the telescope tracking the asteroid over the length of the
exposure. Gianluca Masi/Virtual Telescope.
2020 CG2 was discovered on 14 February 2020 (three days before its closest approach to the Earth) by the Zwicky Transient Facility at Palomar Observatory in California. The
designation 2020 CG2implies that it was the 55th asteroid (asteroid G2 -
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 G2 = 7 + (24 X 2) = 55)
discovered in the first half of February 2020 (period 2020 C).
The calculated orbit of 2020 CG2. JPL Small Body Database.
2020 CG2 has a 892 day (2.44 year) orbital period and an eccentric orbit
tilted at an angle of 8.11° to the plane of the Solar System, which
takes it from 0.97 AU from the Sun (i.e. 97% of he average distance at
which the Earth orbits the Sun) to 2.66 AU from the Sun (i.e. 266% of
the
average distance at which the Earth orbits the Sun, and considerably outside the orbit of 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). This
means that close
encounters between the asteroid and Earth occasionally occur, with the
last having occurred in January 2008, and the next predicted for May 2027.
See also...
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