Asteroid 2017 TE5 passed by the Earth at a distance of about 513 850
km (1.34 times the average distance between the Earth and the Moon, or
0.34% of the distance between the Earth and the Sun), slightly before 11.10 am
GMT on Tuesday 17 October 2017. There was no danger of
the asteroid hitting us, though were it to do so it would not have
presented a significant threat. 2017 TE5 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.
Image of 2017 TE50 taken on 17 October 2017 from Ceccano in Italy with the Elena Telescope. The
asteroid is the point in the
centre of the picture. The longer lines are stars, their elongation
being caused by the telescope tracking the asteroid over the length of
the exposure, in this case three 90 second exposures, giving each star a triple line. Gianluca Masi/Virtual Telescope.
2017 TE5 was discovered on 14 October 2017 (three 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 2017 TE5 implies that it was the 130th asteroid (asteroid E5)
discovered in the first half of October 2017 (period 2017 T).
The calculated orbit of 2017 TE5. Minor Planet Center.
2017 TE5 has an 899 day orbital period and an eccentric orbit
tilted at an angle of 10.3° to the plane of the Solar System, which
takes it from 0.92 AU from the Sun (i.e. 92% of he average distance at
which the Earth orbits the Sun)
to 2.73 AU from the Sun (i.e. 273% of
the
average distance at which the Earth orbits the Sun, considerably more than
the 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 the asteroid has occasional close encounters with the Earth, with the last thought to have happened in January 2013.
See also...
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