Asteroid 2015 BM510 passed by the Earth at a distance of 5 311 000 km (13.82 times the average distance between the Earth and the Moon, or 3.5 % of the average distance between the Earth and the Sun), slightly after 9.00 pm GMT on Tuesday 10 February 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2015 BM510 has an estimated equivalent diameter of 18-57 m (i.e. it is estimated that a spherical object with the same volume would be 18-57 m in diameter), and an object of this size would be expected to break up in the atmosphere between 24 and 7 km above the ground, with only fragmentary material reaching the Earth's surface.
The calculated orbit of 2015 BM510. JPL Small Body Database.
2015 BM510 was discovered on 25 January 2015 (sixteen days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2015 BM510 implies that it was the 12 762nd asteroid (asteroid M51-) discovered in the second half of January 2015 (period 2015 B).
2015 BM510 has a 336 day orbital period, with an elliptical orbit tilted at an angle of 1.6° to the plain of the Solar System which takes in to 0.83 AU from the Sun (83% of the distance at which the Earth orbits the Sun) and out to 1.06 AU (6% further away from the Sun than the Earth). This means that close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in July 2014 and the next predicted in February 2016. Although it does cross the Earth's orbit and is briefly further from the Sun on each cycle, 2015 BM510 spends most of its time closer to the Sun than we are, and is therefore classified as an Aten Group Asteroid.
See also...
Asteroid 2013 BS45 passed by the Earth at a distance of 13 380 000 km (34.8 times the average distance between the Earth and the Moon, or 8.9 % of the average distance between the Earth and the Sun), slightly after 11.15 am GMT on Monday 9 February...
Asteroid 2015 CM passed by the Earth at a distance of 3 236 000 km (8.42 times the average distance between the Earth and the Moon, or 2.2 % of the average distance between the Earth and the Sun), slightly before 8.40 am GMT on Monday 9 February...
Asteroid 2015 CL passed by the Earth at a distance of 1 659 000 km (4.32 times the average distance between the Earth and the Moon, or 1.1 % of the average distance between the Earth and the Sun), at about 1.20 slightly before 10.40 pm GMT on Sunday 8 February...
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