Asteroid 2019 FL1 passed by the Earth at a distance of about 1 090 000
km (2.83 times the average distance between the Earth and the Moon, or
0.73% of the distance between the Earth and the Sun), slightly after 6.05 am
GMT on Sunday 31 March 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 FL1 has an estimated
equivalent
diameter of 7-25 m (i.e. it is estimated that a spherical object
with
the same volume would be 7-25 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 37 and 20 km above the ground, with only fragmentary material
reaching the Earth's surface.
The calculated orbit of 2019 FC1. JPL Small Body Database.
2019 FL1 was discovered on 29 March 2019 (two days before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey,
which is located in the Catalina Mountains north of Tucson. The
designation 2019 FL1 implies that it was the 35th asteroid (asteroid L1 -
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 1 = 11 + 24 = 35)
discovered in the second half of March 2019 (period 2019 F).
2019 FL1 is
calculated to have
an 568 day orbital period and an eccentric orbit
tilted at an angle of 6.90° to the plane of the Solar System, which
takes it from 0.78AU from the Sun (i.e. 78% of the the average distance
at
which the Earth orbits the Sun) to 1.90 AU from the Sun (i.e. 190% of
the
average distance at which the Earth orbits the Sun, more than the
distance at which the planet Mars orbits). 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 the Earth are quite common, with the
last calculated to have happened in September 2009 and the next predicted
for September 2025. The asteroid also has occasional close encounters
with the planet Venus, with the next predicted to occur in November 2062.
See also...
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