Friday 15 May 2015

Asteroid 2015 JC1 passes the Earth.

Asteroid 2015 JC1 passed by the Earth at a distance of 1 360 000 km (3.54 times the average distance between the Earth and the Moon, or 9.09% of the average distance between the Earth and the Sun), slightly after 5.50 pm GMT on Friday 8 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 JC1 has an estimated equivalent diameter of 7-23 m (i.e. it is estimated that a spherical object with the same volume would be 7-23  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 36 and 20 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2015 JC1. JPL Small Body Database.

2015 JC1 was discovered on 12 May 2015 (four days after its closest approach to the Earth) by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation 2015 JC1 implies that it was the 76th asteroid (asteroid C1) discovered in the first half of May 2015 (period 2015 J). 

2015 JC1 has an 602 day orbital period and an eccentric orbit tilted at an angle of 6.31° to the plane of the Solar System, which takes it from 0.67 AU from the Sun (i.e. 67% of the average distance at which the Earth orbits the Sun, inside the orbit of Venus) to 2.12 AU from the Sun (i.e. 212% of the average distance at which the Earth orbits the Sun, considerably more than the average distance at which the planet Mars orbits the Sun). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This also means that close encounters between 2015 HQ171 and the Earth are quite common, with the last having occurred in May 1972 next predicted for December 2024. The asteroid is also predicted to have occasional close encounters with the planet Venus, with the last being thought to have occured in May 1972.

See also...

Asteroid 2015 HQ171 passed by the Earth at a distance of 446 400 km (1.16 times the average distance between the Earth and the Moon, or 2.98% of the average distance between the Earth and the Sun), slightly after 3.50 am GMT on Saturday 2 May 2015. There was no danger of the asteroid hitting us...
 
Asteroid 2015 FT33 passed by the Earth at a distance of 12 570 000 km (32.7 times the average distance between the Earth and the Moon, or 8.40% of the average distance between the Earth and the Sun), slightly before 6.50 am GMT on Friday 1 May...


Asteroid 2011 EX4 passed by the Earth at a distance of 11 000 000 km (28.6 times the average distance between the Earth and the Moon, or 7.35% of the average distance between the Earth and the Sun), slightly after 1.20 am GMT on Thursday 30 April 2015...

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