Thursday 5 November 2015

Asteroid 2015 TR238 passes the Earth.

Asteroid 2015 TR238 passed by the Earth at a distance of 18 510 000 km (48.2 times the average distance between the Earth and the Moon, or 12.4% of the average distance between the Earth and the Sun), slightly after 8.55 am on Friday 30 October 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2015 TR238 has an estimated equivalent diameter of 17-54 m (i.e. it is estimated that a spherical object with the same volume would be 17-54  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 27 and 8 km above the ground, with only fragmentary material reaching the Earth's surface.


 The calculated orbit of 2015 TR238. JPL Small Body Database.


2015 TR238 was discovered on 15 October 2015 (fifteen 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 TR238 implies that the asteroid was the 5968th object (object R238) discovered in the first half  of October 2015 (period 2015 T).

2015 TR238 has an 1381 day orbital period and an eccentric orbit tilted at an angle of 3.22° to the plane of the Solar System that takes it from 1.12 AU from the Sun (i.e. 112 % of the average distance at which the Earth orbits the Sun) to 3.74 AU from the Sun (i.e. 374% of the average distance at which the Earth orbits the Sun, considerably over twice the distance at which the planet Mars orbits). It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is always outside the Earth's orbit). 

See also...

http://sciencythoughts.blogspot.co.uk/2015/11/asteroid-2015-tf-passes-earth.htmlAsteroid 2015 TF passes the Earth.         Asteroid 2015 TF passed by the Earth at a distance of 11 550 000 km (30.0 times the average distance between the Earth and the Moon, or 7.72% of the average distance between the Earth and the Sun), slightly after 4.45 am GMT on Tuesday 27...
 
 
http://sciencythoughts.blogspot.co.uk/2015/11/fireball-over-northern-europe.htmlFireball over northern Europe.         Eyewitnesses across much of northern Europe reported seeing a bright fireball in the sky moving southwest to northeast at about 6.05 pm GMT on Saturday 31 October 2015. The event was seen from the Netherlands, Germany, Denmark, southern...
Asteroid 1998 XN2 passed by the Earth at a distance of 11 610 000 km (30.2 times the average distance between the Earth and the Moon, or 7.76% of the average distance between the Earth and the Sun), slightly before 2.55 pm GMT on Sunday 25 October...
 
 
 
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