Scientists study the asteroid Bennu
NASA believes the asteroid Bennu the most potentially dangerous for the Earth object. It may fall on our planet between 2169 and 2199 years. Research has shown unusual activity this heavenly body.
The analysis of data collected by the automatic interplanetary spacecraft OSIRIS-REx for six months showed a small near-earth body of Bennu, which is called “asteroid Apocalypse”, is fraught with many secrets.
He was like a diamond, formed far away from its orbit, the rotation speed increases, on the surface there are traces of water and primordial matter, and the surface of the asteroid consists of hundreds of boulders. Корреспондент.net tells details.
What scientists have learned about Bennu
On March 20 at the international scientific conference on planetary science (Lunar and Planetary Science Conference), as well as in a series of articles published in the journal Nature, scientists reported on data collected by NASA’s mission to asteroid Bennu, called Origins Spectral Interpretation Resource Identification Security Regolith Explorer.
Benn is one of the darkest objects in the Solar system. Diameter carbonaceous asteroid is about 500 meters. It is part of the Apollo group, makes one revolution around the Sun for 1.2 years, orbits, crossing the orbits of Earth and Mars, and refers to potentially hazardous objects.
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Mission OSIRIS-REx (in the myth. the Bennu bird – the symbol of the rebirth of Osiris) was launched in 2016. Its main purpose is to collect and deliver to Earth the maximum time the quantity of material from the surface of the asteroid. Also, within two years OSIRIS-REx will remotely study the Bennu. Return it needs in 2023.
“We are studying asteroids like Bennu in order to better understand the history of our Solar system. The spacecraft OSIRIS-Rex will be able to help us answer some very important questions related to where do we come from,” said Laurie glaze, acting Director of the division for planetary science at NASA.
The eruption of material into space. The spacecraft went into orbit around Bennu in early January and immediately ran into a surprise – the release of small particles from the surface of the asteroid in a plume with a speed of several meters per second. In February has recorded ten such emissions.
The reason for the formation of these geysers may be the transformation of water ice to vapor when heat from the Sun. OSIRIS-REx is on the orbit of Bennu during the closest approach to the Sun. Similar processes occur for other known active asteroid during the approach to the Sun. The exact answer is not yet known.
Traces of water in minerals on the surface of asteroid Bennu, scientists discovered in December last year. Scientists adhere to the theory that water on Earth “brought” the asteroids, and with it, perhaps, life.
“The presence of traces of water in minerals Benn confirmed that he would help to obtain data on the chemical and isotopic composition of primordial matter of the planets. When samples of his species will come to Earth, scientists will get a lot of information about the early evolution of the Solar system,” says Amy Simon, an employee of the space flight Center of NASA.
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The diamond shape. Externally Benn, similar to a spinning top or a rough diamond. The average diameter of the asteroid is estimated at 490 meters in the polar regions it is already, and widely in the Equatorial region, where is located the annular ridge.
Nedra Bennu is very chaotic way and contain a large number of voids and high-density areas. This suggests that the asteroid came from fragments of other large celestial bodies that collided in the main asteroid belt.
The age of the asteroid. A large number of impact craters on the ridged surface of Bennu suggests that the age of the asteroid is about a billion years. They also indicate that the domed shape formed at once, and not under the influence of the Sun.
Geological activity. Material at the poles of the asteroid “slide” towards the equator, indicating geological activity.
Large boulders have dimensions of from 40 to 100 metres and are mainly located near the polar regions (this is due to the migration of small boulders and regolith to the Equatorial regions). There are suggestions that the large boulders are fragments of the parent body of the asteroid.
Astronomers also found that the rotation period of the asteroid Bennu is reduced by about one second every hundred years.
This can lead to its destruction within a few million years, and for the acceleration process, according to scientists, responsible YORP-effect, which consists in changing the speed of rotation of the asteroid asymmetrical shapes under the influence of solar radiation.
Benn was very similar in shape and color to another celestial body, the asteroid Ryugu, which is now being studied by the Japanese mission Hayabusa-2.
The interest of scientists asteroids due to the fact that their surfaces can meet protocolecho particles of the nebula. The elemental composition of such bodies similar to the composition of the Sun, and the age is estimated at more than 4.5 billion years, which almost corresponds to the age of our planetary system.
On-Board devices are not able to completely reveal all the secrets of the chemical composition of these objects. Therefore, researchers are spending billions of dollars on the delivery of soil samples from the surface of Itokawa.
This will help to explain the very beginning of the Solar system, the Earth and other planets, and how life originated.
Hayabusa-2 is already close to the surface of the Ryugu and preparing to throw a bomb at the beginning of April. Japanese specialist not only want to collect deep, pure samples of asteroid matter, but to compare, it looks like the surface before and after the appearance of man-made crater.
Its orbit has an elongated shape and crosses the orbits of Earth and Mars, and the diameter is estimated at about 900 metres.
March 19 in the journal Science has been published the article with the details of the first study Ryugu. It turned out that it is an accumulation of fragments of a large celestial body which once could contain water ice and organic molecules, and also have an internal heat source in the form of radioactive elements.
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Age surface Ryugu is 10-100 million years. Boulders on the surface probably represent the fragments of his “ancestor”.
In addition, scientists say that the Ryuga is a porous body, the density of which is only slightly more than the density of water. In addition, he was the dark celestial body of all visited units.
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