The asteroid 2013 RN9 is predicted to fly past the Earth at a distance of 11 200 000 km (29 times the distance to the Moon) slightly after 8.35 am on Wednesday 9 October 2013. This is not a particularly close approach, and there is no chance of the asteroid hitting us, though should this happen at some point in the future then it might present a slight risk. 2013 RN9 currently has an estimated size of 19-99 m (though this will probably be resolved better in the next few hours), and while a 19 m object would be predicted to break up in the atmosphere at around 22 km above the Earth's surface, with only fragmentary material reaching the ground, a 99 m object could potentially reach the surface of the planet, leaving a crater in excess of a kilometer wide, which would cause considerable devastation over a wide area, and probably cause climate problems for several years (though it would not be likely to cause a major global extinction event).
2013 RN9 was discovered by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson, on 2 September 2013. The name 2013 RN9 implies the 238th such object discovered in the first half of September 2013 (period 2013 R).
2013 RN9 is calculated to have a 711 day orbital period, with an orbit that crosses those of the Earth and Mars. At its perihelion (closest point to the Sun on its orbit) it is 0.83 AU from the Sun (83% of the average distance between the Earth and the Sun, and at its aphelion (furthest point from the Sun during its orbit) it is slightly over 2.3 AU from the Sun (2.3 times as distant as the Earth and outside the orbit of Mars). As its average distance from the Sun is greater than the Earth's but it crosses our orbit it is classed as an Apollo Group Asteroid.
See also Asteroid 2013 RX73 to fly past the Earth on Wednesday 9 October 2012, Asteroid 2013 TO4 to pass the Earth on Tuesday 8 October 2013, Asteroid 2013 SM20 to pass the Earth on Tuesday 8 October 2013, Asteroid (350751) 2002 AW to pass the Earth on Monday 7 October 2013 and Asteroid 2013 SC21 to pass the Earth on Monday 7 October 2013.
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