Asteroid 2020 TP1 passed by the Earth at a distance of about 386 600 km (1.01 times the average distance between the Earth and the Moon, or 0.26% of the distance between the Earth and the Sun), at abput 2.35 pm GMT on Thurday 8 October 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 TP1 has an estimated equivalent diameter of 8-26 m (i.e. it is estimated that a spherical object with the same volume would be 8-26 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 20 km above the ground, with only fragmentary material reaching the Earth's surface.
2020 TP1 was discovered on 9 October 2020 (the day after its closest approach to the Earth), by he 0.5-m Asteroid Terrestrial-Impact Last Alert System telescope on Mauna Loa in Hawaii. The designation 2020 TP1 implies that it was the 39th asteroid (asteroid P1 - 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 P1 = (24 x 1) + 15 = 39) discovered in the first half of October 2020 (period 2020 T - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).
2020 TP1 has a 1229 day (3.36 year) orbital period, with an elliptical
orbit tilted at
an angle of 1.14° to the plain of the Solar System which takes in to
0.79 AU from the Sun (79% of the distance at which the Earth orbits the
Sun) and out to 3.70 AU (3.70% of the distance at which the Earth orbits
the Sun, and more than 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 2020TP1 has occasional close encounters between the asteroid and Earth, with the last thought to have happened in May 1926 and the next predicted in May 2072. The asteroidalso has occasional close encounters with the planets Mars, which it last cam close to in September 1976 and is next predicted to pass in October 2196, and Jupiter, which it last came close to in November 1907 and is expected to pass again in March 2074. Asteroids which make close passes to multiple planets are considered to be in unstable orbits, and are often eventually knocked out of these orbits by these encounters, either being knocked onto a new, more stable orbit, dropped into the Sun, knocked out of the Solar System or occasionally colliding with a planet.
See also...
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