Astronomers have spotted and obtained observations of the smallest yet one of the brightest asteroid ever revealing its details.
Named 2015 TC25, the asteroid is just 2 meters (6 feet) in diameter and according to the team at University of Arizona, the asteroid reflects about 60 percent of the sunlight that falls on it. The asteroid has been studied extensively by Earth-based telescopes during a close flyby that saw the micro world sailing past Earth at 128,000 kilometers, a mere third of the distance to the moon. For the observation of the asteroid, scientists used data from four different telescopes,
Discovered by the UA’s Catalina Sky Survey last October, 2015 TC25 is similar to a rare type of highly reflective meteorite called an aubrite. Aubrites consist of very bright minerals, mostly silicates, that formed in an oxygen-free, basaltic environment at very high temperatures. Only one out of every 1,000 meteorites that fall on Earth belong to this class.
Small near-Earth asteroids such as 2015 TC25 are in the same size range as meteorites that fall on Earth. Astronomers discover them frequently, but not very much is known about them as they are difficult to characterize. By studying such objects in more detail, astronomers hope to better understand the parent bodies from which these meteorites originate.
Asteroids are remaining fragments from the formation of the solar system that mostly orbit the sun between the orbits of Mars and Jupiter today. Near-Earth asteroids are a subset that cross Earth’s path. So far, more than 15,000 near-Earth asteroids have been discovered.
The discovery also is the first evidence for an asteroid lacking the typical dust blanket — called regolith — of most larger asteroids. Instead, 2015 TC25 consists essentially of bare rock. The team also discovered that it is one of the fastest-spinning near-Earth asteroids ever observed, completing a rotation every two minutes.
Probably, 2015 TC25 is what planetary scientists call monolithic, meaning it is more similar to a “solid rock” type of object than a “rubble pile” type of object like many large asteroids, which often consist of many types of rocks held together by gravity and friction. Bennu, the object of the UA-led OSIRIS-REx sample return mission, is believed to be the latter type.
The study about the asteroid is published in The Astronomical Journal.