Wednesday 29 April 2020

Asteroid 2020 HM6 passes the Earth.

Asteroid 2020 HM6 passed by the Earth at a distance of about 162 900 km (0.42 times the average  distance between the Earth and the Moon, 0.11% of the distance between the Earth and the Sun, or 399 times the distance at which the International Space Station orbots the Earth, and 4.55 times the distance of satellites in geostationary orbits), slightly after 5.50 am GMT on Wednesday 22 April April 2020. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2020 HM6 has an estimated equivalent diameter of 9-29 m (i.e. it is estimated that a spherical object with the same volume would be 9-29 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 32 and 17  km above the ground, with only fragmentary material reaching the Earth's  surface.

The calculated orbit of 2020 HM6. JPL Small Body Database.

2020 HM6 was discovered on 24 April 2020 (two days after its closest encounter with 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 2020 HM6 implies that the asteroid was the 156th object (asteroid M6 - 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, so that M6 = (24 x 6) + 12 = 156) discovered in the second half of April 2020 (period 2020 H).

2020 HM6 has a 1119 day (3.06 year) orbital period and an eccentric orbit tilted at an angle of 2.29° to the plane of the Solar System, which takes it from 0.76 AU from the Sun (i.e. 76% of he average distance at which the Earth orbits the Sun) to 3.46 AU from the Sun (i.e. 346% of the average distance at which the Earth orbits the Sun, and more that twice the 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 means that 2020 HM6 has occassional close encounters with the Earth, with the next predicted in May 2023.

See also...

https://sciencythoughts.blogspot.com/2020/04/first-protein-of-extraterrestrial.htmlhttps://sciencythoughts.blogspot.com/2020/04/asteroid-2020-hf-passes-earth.html
https://sciencythoughts.blogspot.com/2020/04/asteroid-2020-gn2-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/04/possibility-of-seeing-puppid-meteor.html
https://sciencythoughts.blogspot.com/2020/04/asteroid-2020-ga2-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/04/the-lyrid-meteor-shower.html
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