Asteroid 2017 DS109 passed by the Earth at a distance of 353 300 km (0.92
times the average distance between the Earth and the Moon, 0.24% of
the average distance between the Earth and the Sun), slightly before 2.30 pm GMT
on Sunday 5 March 2017. There was no danger of the asteroid
hitting us, though had it done so it would have presented no threat.
2017 DS109 has an estimated equivalent diameter of 12-38 m (i.e. it is
estimated that a spherical object with the same volume would be 12-38 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 12 km above the ground, with only fragmentary material
reaching the Earth's surface.
The calculated orbit of 2017 DS109. Minor Planet Center.
2017 DS109 was discovered on 27 February 2017 (six days after its closest approach to the Earth) by the University of Hawaii's PANSTARRS
telescope on Mount Haleakala on Maui. The designation 2017 DS109 implies
that it was the 2743rd asteroid (asteroid S109) discovered in the second
half of February 2017 (2017 D).
2017 D3S109 has a 1121 day orbital period and an eccentric orbit
tilted at an angle of 4.16° to the plane of the Solar System, which
takes it from 0.91 AU from the Sun (i.e. 91% of he average distance at
which the Earth orbits the Sun) to 3.31 AU from the Sun (i.e. 3.31% of
the
average distance at which the Earth orbits the Sun, considerably over twice distance at which the planet 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 common, with the
last having occurred in February 2014 and the next predicted
in April 2020.
See also...
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