Asteroid 2015 KK120 passed by the Earth at a distance of 9 323 000 km (24.3 times the average distance between the Earth and the Moon, or 6.23% of the average distance between the Earth and the Sun), slightly after 2.15 am GMT on Sunday 31 May 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2015 KK120 has an estimated equivalent diameter of 4-14 m (i.e. it is estimated that a spherical object with the same volume would be 4-14 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 42 and 28 km above the ground, with only fragmentary material reaching the Earth's surface.
The calculated orbit of 2015 KK120. JPL Small Body Database.
2015 KK120 was discovered on 20 May 2015 (eleven days before its closest approach to the Earth) by the Dark Energy Camera on the Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory in La Serena, Chile. The designation 2015 KK120 implies that it was the 3010th asteroid (asteroid K120) discovered in the secondt half of May 2015 (period 2015 K).
While 2015 KK120 occasionally comes near to the Earth, it does not actually cross our orbital path. It has an elliptical 644 day orbit, at an angle of 2.41° to the plane of the Solar System, that takes it from 1.07 AU from the Sun (1.07 times the average distance at which the Earth orbits the Sun), slightly outside our orbit, to 1.84 AU from the Sun, (1.64 times the distance at which the Earth orbits the Sun and more than the average distance at which the planet Mars orbits the Sun). As a Near Earth Object that remains strictly outside the orbit of the Earth it is classed as an Amor Family Asteroid.
See also...
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