Tuesday 19 May 2020

Asteroid 2019 JH7 passes the Earth.

Asteroid 2019 JH7 passed by the Earth at a distance of about 11 573 000 km (30.1 times the average distance between the Earth and the Moon, or 7.74% of the distance between the Earth and the Sun), slightly before 4.30 pm GMT on Tuesday 12 May 2020. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2019 JH7 has an estimated equivalent diameter of 2-7 m (i.e. it is estimated that a spherical object with the same volume would be 2-7 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 more than 36 km above the ground, with only fragmentary material reaching the Earth's  surface.

Asteroid 2019 JH7 imaged on 15 May 2019 from London, England. Image is a composite made up of 40 one second exposures. Asteroid is the short solid line indicated by the red circle, which has moved only slightly over the course of the image gathering, while the longer lines of dots are stars that have moved considerably in the same time. Northolt Branch Observatories/Facebook.

2019 JH7 was discovered on 14 May 2019 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 2019 JH7 implies that the asteroid was the 176th object (asteroid H7 - 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 H7 = (24 x 7) + 8 = 176) discovered in the first half of May 2019 (period 2019 J - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).

The calculated orbit of 2019 JH7. JPL Small Body Database Browser.

2019 JH7 has a 360 day (0.99 year) orbital period, with an elliptical orbit tilted at an angle of 0.85° to the plain of the Solar System which takes in to 0.70 AU from the Sun (70% of the distance at which the Earth orbits the Sun, and slightly inside the orbit of the planet Venus) and out to 1.28 AU (28% further away from the Sun than the Earth). This means that close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in May 2019 and the next predicted in May 2021. Although it does cross the Earth's orbit and is briefly further from the Sun on each cycle, 2019 JH7 spends most of its time closer to the Sun than we are, and is therefore classified as an Aten Group Asteroid. The asteroid also has occasional close encounters with the planet Venus, with the last having happened in July 2017, and the next predicted for July this year (2020).

See also...

https://sciencythoughts.blogspot.com/2020/05/asteroid-2000-ka-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/05/nitrogen-bearing-organic-molecules-from.html
https://sciencythoughts.blogspot.com/2020/05/asteroid-2020-jb1-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/05/asteroid-2020-hc6-passes-earth.html
https://sciencythoughts.blogspot.com/2020/05/asteroid-2020-hl6-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/05/asteroid-2020-jn-passes-earth.html
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