Sunday 7 April 2019

Asteroid 2019 FL1 passes the Earth.

Asteroid 2019 FL1 passed by the Earth at a distance of about 1 090 000 km (2.83 times the average distance between the Earth and the Moon, or 0.73% of the distance between the Earth and the Sun), slightly after 6.05 am GMT on Sunday 31 March 2019. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2019 FL1 has an estimated equivalent diameter of 7-25 m (i.e. it is estimated that a spherical object with the same volume would be 7-25 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 37 and 20 km above the ground, with only fragmentary material reaching the Earth's surface.

 The calculated orbit of 2019 FC1. JPL Small Body Database.

2019 FL1 was discovered on 29 March 2019 (two days before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2019 FL1 implies that it was the 35th asteroid (asteroid L1 - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 24, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that 1 = 11 + 24 = 35) discovered in the second half of March 2019 (period 2019 F).

2019 FL1 is calculated to have an 568 day orbital period and an eccentric orbit tilted at an angle of 6.90° to the plane of the Solar System, which takes it from 0.78AU from the Sun (i.e. 78% of the the average distance at which the Earth orbits the Sun) to 1.90 AU from the Sun (i.e. 190% of the average distance at which the Earth orbits the Sun, more than the distance at which the planet Mars orbits). 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 means that close encounters between the asteroid and the Earth are quite common, with the last calculated to have happened in September 2009 and the next predicted for September 2025. The asteroid also has occasional close encounters with the planet Venus, with the next predicted to occur in November 2062.
 
See also...
 
http://sciencythoughts.blogspot.com/2019/04/asteroid-7-iris-reaches-oposition.htmlhttp://sciencythoughts.blogspot.com/2019/03/asteroid-2019-fc1-passes-earth.html
https://sciencythoughts.blogspot.com/2019/03/fireball-meteor-over-new-york-state.htmlhttps://sciencythoughts.blogspot.com/2019/03/possible-second-large-impact-crater.html
https://sciencythoughts.blogspot.com/2019/03/discovery-of-large-impact-crater.htmlhttps://sciencythoughts.blogspot.com/2019/03/asteroid-2019-fa-passes-earth.html
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