Asteroid 2020 KR passed by the Earth at a distance of about 397 500 km (1.04 times the average distance between the Earth and the Moon, or 0.27% of the distance between the Earth and the Sun), slightly after 0.10 am GMT on Wednesday 20 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. 2020 KR has an estimated equivalent diameter of 5-14 m (i.e. it is estimated that a spherical object with the same volume would be 5-14 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 40 and 28 km above the ground, with only fragmentary material reaching the Earth's surface.
300 second image of 2000 KA taken with the Elena Planetwave 17" Telescope at Ceccano in Italy on 12 May 2020. The asteroid is the small point at the centre of the image, indicated by the white arrow, the longer lines are stars, their elongation being caused by the telescope tracking the asteroid over the length of the exposure. Gianluca Masi/Virtual Telescope.
2020 KR was discovered on 16 May 2020 (four days before its closest encounter with the Earth) by the University of Hawaii's PANSTARRS telescope. The designation 2020 KR implies that it was the 17th asteroid (asteroid R - 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 R = 17) discovered in the second half of May 2020 (period 2020 K - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).
2020 KR has an 625 day (1.71 year) orbital period and an eccentric orbit tilted at an angle of 9.43° to the plane of the Solar System, which takes it from 0.78 AU from the Sun (i.e. 78% of the the average distance at which the Earth orbits the Sun) to 2.07 AU from the Sun (i.e. 207% of the average distance at which the Earth orbits the Sun, more than the distance at which 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 close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in November 1985 and the next predicted in October 2025. Asteroid 2020 KR also has regular close encounters with the planet Venus, which it last came close to in August 1959 and is next expected to approach in July this year (2020), and Mars, which it last came close to in February 1972.
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