Astronomers have measured the smallest near-earth asteroid

Астрономы измерили самый маленький околоземный астероид

Planetary scientists from the University of Arizona for the first time accurately measured the size, mass and other properties of the small near-earth asteroid object 2015 TC2, whose diameter is only two meters, according to a paper published in the Astronomical Journal.

“Study of physical properties of small near-earth asteroids is extremely important to us for the reason that they are a greater threat to human existence. The diameter of the meteoroid that exploded over Chelyabinsk and injured dozens of people, was only 20 meters,” said Stephen Tegler (Stephen Tegler) from the University of Arizona in Tucson (USA).

In the last few decades, scientists around the world actively monitor the near-earth asteroids and hold a kind of cosmic “census” among them, trying to understand how dangerous they are for humanity. Asteroids in near-earth space there are so many that astronomers had to create a special scale to assess how likely they fall to the Ground.

Despite all this and the huge number of asteroids discovered in recent years using ground-based telescopes and infrared space Observatory WISE, many of the larger asteroids and countless smaller objects the size of Chelyabinsk meteorite that fell to Earth in February 2013.

As reported by NASA back in 2011 at the first presentation of the catalog of NEOWISE, today we only know about five thousand asteroids about one hundred meters, while their total number is estimated at tens of thousands. The number of smaller objects within the main asteroid belt may be more and more to reach a million.

Tegler, and a number of American astronomers under the guidance of Vishnu Reddy (Reddy Vishnu), the first to study the properties of the smallest of them – celestial bodies TC2 2015, open in October 2015 with ground-based telescopes of NASA.

Says Reddy, observations of similar objects are interesting to astronomers for several reasons. Apart from their obvious threat to Earth, a little “cousins” of the Chelyabinsk meteorite from the scientific point of view is a curious fact that all the known meteorites that fall to Earth in the recent or distant past, formed as a result of the fall and burning of small asteroids, whose diameter does not exceed 20 meters.

2015 TC2, most likely, will never be able to become a meteorite the size and weight are too small to survive “a date” with the Earth’s atmosphere. According to calculations of scientists, its diameter ranges from 1.7 to 3.3 meters, it has a fairly bright surface, which is composed of silicic rocks and rotates at high speed, making a turn about every two minutes.

His ancestor, judging by the infrared spectrum of rocks 2015 TC2, was a large 113-kilometer asteroid Nisa, living in the main asteroid belt between the orbits of Mars and Jupiter. This asteroid, as today’s scientists believe, is a fragment of the core or lower layers of the mantle of one of the “germ” of the planets inhabiting the Solar system in the first years of her life.

Further study of such objects, according to Reddy, will help us more accurately determine how to change their orbit in the following years, and count their danger to civilization and life on Earth.