Tuesday 15 October 2013

Asteroid 2013 SR passes the Earth.

Asteroid 2013 SR passed by the Earth at a distance of 10 440 000 km (slightly over 27 times as distant as the Moon) slightly before 8.30 am local time on Saturday 12 October 2013. There was no danger of the asteroid hitting us and even if it had it would have presented only a minor threat. 2013 SR is estimated to have a diameter of between 28 and 90 m, and objects of this size would generally be expected to break up in the atmosphere before hitting the ground, though an object towards the upper end of this range would probably cause considerable localized damage.

The calculated orbit of 2013 SR. JPL Small Body Database Browser. 

2013 SR was discovered on 23 September 2013 by the University of Arizona's Catalina Sky Survey in the Catalina Mountains north of Tucson. The name 2013 SR implies that it was the 17th asteroid discovered in the second half of September 2013 (period 2013 S).

While 2013 SR occasionally comes near to the Earth, it does not actually cross our orbital path. It has an elliptical 675 day orbit that takes it from 1.03 AU from the Sun (1.03 times the distance at which the Earth orbits the Sun), slightly outside our orbit, to slightly under 2 AU from the Sun, outside the orbit of Mars, so unless an encounter with another body causes it's orbital path to alter in a very specific way (highly unlikely) there is no chance of it hitting the Earth. Close encounters between 2013 SR and the Earth are thought to be rare, the last is estimated to have occurred in September 1904 and the next is predicted to occur in December 2109. As a Near Earth Object that remains strictly outside the orbit of the Earth it is classed as an Amor Family Asteroid.

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