Astronomers Identify Smallest Asteroid Ever Characterized in Detail

A team led by astronomers at University of Arizona's Lunar and Planetary Laboratory have identified the smallest asteroid ever to be described and characterized in detail.

Their discovery, described in a paper published in The Astronomical Journal, was made using optical, infrared and radar data on such a small asteroid, which is about two meters in diameter. The researchers noted that the asteroid could be a meteoroid, a free-floating meteorite in space that hasn't entered the Earth's atmosphere and made it to ground, yet.

"If we can discover and characterize 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," said Vishnu Reddy, an assistant professor at the University of Arizona's Lunar and Planetary Laboratory and lead author of the study, in a press release.

For their discovery, the researchers used data from four different telescopes, including the University of Hawaii/NASA IRTF, USRA/Arecibo Planetary Radar, New Mexico Institute of Mining and Technology/Magdalena Ridge Observatory, Northern Arizona University and Lowell Observatory/Discovery Channel Telescope.

First discovered in October by the UA's Catalina Sky Survey, the asteroid, dubbed as 2015 TC25, is considered to be one of the brightest near-Earth asteroids to be discovered. The 2015 TC25 was extensively studied by a number of Earth-based satellites during its close flyby on Earth at 128,000 kilometers.

Data from the NASA Infrared Telescope Facility and Arecibo Planetary Radar revealed that the surface of 2015 TC25 is similar to aubrite, a rare type of highly reflective meteorite. Due to its rarity, only one out of 1,000 meteorites that fall on Earth is aubrites. Aubrites consist of very bright minerals, mostly silicate. These minerals form in an oxygen-free, basaltic environment at very high temperatures.

Further analysis of the new observations showed that 2015 TC25 don't have the usual dust blankets like larger asteroids. Additionally, the researchers observed that 2015 TC25 is one of the fastest spinning near-Earth asteroids ever observed, completing one rotation every two minutes.

The researchers believe that the 2015 TC25 is chipped away from its parent 44 Nysa.