Asteroid 2015 CA40 passed by the Earth at a distance of 2 419 000 km (6.32 times the average distance between the Earth and the Moon, or 1.6% of the average distance between the Earth and the Sun), slightly before 9.50 pm GMT on Monday 23 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 CA40 has an estimated equivalent diameter of 21-73 m (i.e. it is estimated that a spherical object with the same volume would be 21-73 m in diameter), and an object of this size would be expected to break up in the atmosphere between 21 and 3 km above the ground, with only fragmentary material reaching the Earth's surface, although since an object at the upper end of this range would be expected to release an amount of energy equivalent to about 15 megatons of TNT (roughly 1000 times the energy released by the Hiroshima bomb), then being directly underneath it might be fairly unpleasant.
2015 CA40 in the morning of 24 Feb 2015 near 9 UT, some 12 hours after closest approach. Images taken overr a 10-minute timespan at 2 minute intervals and 30 second exposure. My Asteroid Discoveries/Sierra Stars Observatory Network.
2015 CA40 was discovered on 15 February 2015 (eight days before its closest approach to the Earth) by the University of Szeged's Konkoly Observatory in Hungary. The designation 2015 CA40 implies that it was the 1001st asteroid (asteroid A40) discovered in the first half of February 2015 (period 2015 C).
One of the discovery images of 2015 CA40. Marco Langbroek/My Asteroid Discoveries/Konkoly Observatory.
While 2015 CA40 occasionally comes near to the Earth, it does not actually cross our orbital path. It has an elliptical 424 day orbit, at an angle of 15° to the plane of the Solar System, that takes it from 1.004 AU from the Sun (1.004 times the average distance at which the Earth orbits the Sun), slightly outside our orbit, to 1.20 AU from the Sun, (1.20 times the distance at which the Earth 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. This orbit also means that close encounters between 2015 CA40 and the Earth are extremely common, with the last having occured in March 2008 and the next predicted for February 2022.
The calculated orbit of 2015 CA40. JPL Small Body Database.
See also...
Asteroid 2014 EK24 passed by the Earth at a distance of 6 129 000 km (15.94 times the average distance between the Earth and the Moon, or 4.1% of the average distance between the Earth and the Sun), slightly after 5.30 pm GMT on Monday 23 February...
Asteroid 2015 DU passed by the Earth at a distance of 3 068 000 km (7.97 times the average distance between the Earth and the Moon, or 2% of the average distance between the Earth and the Sun), at about 10.00 am GMT on Monday 23 February 2015...
Asteroid 2014 YM9 passes the Earth. Asteroid 2014 YM9 passed by the Earth at a distance of 15 510 000 km (40.35 times the average distance between the Earth and the Moon, or 10.4 % of the average distance between the Earth and the Sun), slightly after 11.10 pm GMT on Thursday 12 February...
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