Wednesday 15 May 2024

Asteroid 2024 JN16 passes the Earth.

Asteroid 2024 JN16 passed by the Earth at a distance of about 25 400 km (0.07 times the average distance between the Earth and the Moon, or 0.017% of the distance between the Earth and the Sun, but more than 62 times as far from the Earth's surface as the International Space Station), with a relative velocity of about 9.26 km per second, slightly before 9.50 am GMT on Tuesday 14 May 2024. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2024 JN16 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) more than 36 km above the ground, with only fragmentary material reaching the Earth's surface.

120 second image of 2024 JN16 taken with the Celestron 14"-F8/8.4 (356/3000 mm) Schmidt-Cassegrain Telescope at Ceccano in Italy on 5 April 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 Project.

2024 JN16 was discovered on 12 May 2024 (two days before its closest approach to the Earth) by Gennady Borisov at the MARGO observatory in Crimea. The designation 2024 JN16 implies that it was the 638th asteroid (object N16 - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 25, with a number added to the end each time the alphabet is ended so that A = 1, A1 = 26, A2 = 51, etc., which means that N16 = 13 + (25 x 16) = 638) discovered in the first half of May 2024 (period 2024 J - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).

The relative positions of 2024 JN16 and the Earth on at 10.00 am GMT on 14 May 2024. JPL Small Body Database.

2024 JN16 is calculated to have a 456 day (1.25 year) orbital period, with an elliptical orbit tilted at an angle of 5.79° to the plain of the Solar System which takes in to 0.89 AU from the Sun (89% of the distance at which the Earth orbits the Sun) and out to 1.43 AU (1.43 times the distance at which the Earth orbits the Sun, somewhat less 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). 

The relative positions of 2024 JN16, the Earth, and the planets of the Inner Solar System on at 10.00 am GMT on 14 May 2024. JPL Small Body Database.

This means that 2024 JN16 has regular close encounters with the Earth, with the last calculated to have happened in November 2019, and the next predicted for January 2032. 2024 JN16 also has occasional close encounters with the planet Venus, with the next predicted for June 2025.

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