Astronomers Have Found Out How The Red Stripes Appeared On The Asteroid Ryugu
Japanese planetary scientists analyzed images that the Hayabusa-2 probe received when it landed on the surface of the Ryugu asteroid and found hints that mysterious deposits of red rocks on its surface formed during its recent approach to the Sun. The scientists' conclusions were published in the scientific journal Science.
"The red rocks on the Ryugu asteroid could have appeared since about 300 thousand years ago its orbit temporarily changed, as a result of which the asteroid got closer to the Sun. Its surface began to warm up more, which is why the deposits of organic matter on its surface turned red," the scientists write.
The Hayabusa-2 probe was launched in early December 2014 to study the Ryugu asteroid, as well as collect rock samples from its surface and deliver them to Earth.
The probe did this in two stages. It first came close to the asteroid's surface in February 2019 and fired a five-gram tantalum bullet into it. When it hit the surface of the asteroid, it should have raised the dust that Hayabusa-2 collected in the sampler.
Two months later, the probe dropped a bomb on Ryuga with about 4.5 kg of octogen, creating a man-made crater on the surface of the asteroid. In July of last year, Hayabusa-2 once again approached the asteroid's surface at the point of explosion, taking supposedly pure samples of the Solar system's primary matter.
However, the images taken by the spacecraft's cameras at the moment of the first approach to the surface made Japanese planetary scientists doubt this. These photos show rock samples that were thrown up by a tantalum bullet.
The fact is that immediately after the arrival of "Hayabusa-2" to Ryugu, scientists noticed that its surface is heterogeneous in its composition. It is covered with alternating bands of red and blue rocks, the nature of which until recently remained a mystery to astronomers.
At the point of the first approach of the probe to the surface of the asteroid, as scientists note, blue rocks predominated, which planetologists associated with the primary matter of the Solar system. At the same time, scientists associated red rocks with the less primitive matter, which fell into the bowels of the asteroid at the time of the death of its progenitor and the formation of Ryugu from its debris.
When scientists began looking at footage of the landing and takeoff of Hayabusa-2, they found that a significant portion of these red rocks looked like sand, which was easily "blown" off the surface of Ryugu by the probe's engines. In the samplers of the device, along with samples of blue primary matter, quite a lot of red rocks got into it.
Such a structure of the asteroid's red regions, according to planetologists, suggests that they appeared on the surface of the celestial body relatively recently, about 300 thousand years ago. According to scientists, this happened as a result of the fact that the orbit of Ryugu at that time changed dramatically, which is why it first came close to the Sun and was covered with a thin layer of red "sand."
The blue stripes on the surface of Ryugu, as scientists note, appeared much later, since some of the red sand was thrown out of the Equatorial regions of the asteroid under the influence of rotation, as well as as a result of the formation of new craters in other parts of its surface. Studying samples of red and blue matter that Hayabusa-2 will deliver to Earth at the end of this year will help scientists test this hypothesis and finally learn the history of the formation of Ryugu.