Asteroid collision detection improves after bright find

Astronomers have discovered more information about the smallest known asteroid – discovered last year – which could help predict potential asteroid collisions on Earth.

Measuring 2 metres in diameter, the asteroid – 2015 TC25 – is also one of the brightest near-Earth asteroids ever discovered, reflecting about 60% of the sunlight that falls on it. Observations suggest the asteroid’s surface is similar to a rare type of highly reflective meteorite – an aubrite.

Vishnu Reddy, an assistant professor at the University of Arizona and first author of the study, said: “This is the first time we have optical, infrared and radar data on such a small asteroid, which is essentially a meteoroid. You can think of it as a meteorite floating in space that hasn't hit the atmosphere and made it to the ground yet."

Aubrites are extremely rare, with 1 of every 1,000 meteoroids that fall to earth classified as such. 2015 TC25 is one of more than 15,000 near-Earth asteroids that have been discovered. Aubrites such as this are made of silicates – bright materials formed in an oxygen free, basaltic environment.

Reddy said: “If we can discover and characterise asteroids and meteoroids this small, then we can understand the population of objects from which they originate: large asteroids, which have a much smaller likelihood of impacting Earth. In the case of 2015 TC25, the likelihood of impacting Earth is fairly small."

This discovery has also revealed that the asteroid is lacking a regolith – the layer of dust – that surrounds larger asteroids. 2015 TC25 is also one of the fastest spinning near-Earth asteroids seen, completing one rotation every two minutes. Researchers believe the asteroid was formed by a collision with its parent, 44 Nysa, an asteroid located between the orbits of Mars and Jupiter.

The study was published in The Astronomical Journal.