Asteroid
2016 VD4 passed by the Earth at a distance of 565 900 km (1.47 times the
average distance between the Earth and the Moon, 0.38% of the average distance
between the Earth and the Sun), at about 5.00 am GMT on Monday 7 November 2016. There was no danger of the asteroid hitting us, though had it
done so it would have presented no threat. 2016 VD4 has an estimated
equivalent diameter of 5-18 m (i.e. it is estimated that a spherical object
with the same volume would be 5-18 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 24 km above the ground, with only fragmentary
material reaching the Earth's surface.
The calculated orbit of 2016 VD4. Minor Planet Center.
2016 VD4 was discovered on 9 November 2016 (two days after 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 2016 VD4 implies that it was the 104th asteroid (asteroid D4)
discovered in the first half of November 2016 (period 2016 V).
2016 VD4 has a 434 day orbital period and an elliptical orbit tilted at
an angle of 11.7° to the plane of the Solar System
that
takes it from 0.71 AU from the Sun (i.e. 71% of the average distance at
which the Earth orbits the Sun, slightly inside the orbit of Venus)
to 1.25 AU from the Sun (i.e. 125% 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 thought to have happened in July this year and the next predicted in May 2022.
See also...
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