About two centuries have passed since we discovered the existence of asteroids, and comets – millennia. However, only in the second half of the twentieth century.as well as century, so that we begin to understand their nature and origin. Revolutioneven allowed us to observe them more closely at that time, especially the spectacular mission . I’ as we know, was going to do much better with the probe and comet 67P/Churyumov-Gerasimenko.
In recent years, the Hayabusa-2 mission has taken center stage in the study of these small celestial bodies, providing not onlybut also because this mission made it possible to collect samples of this Apollo type C, potentially dangerous, discovered in 1999. .
Knes participated in the Hayabusa 2 mission to Ryugu. © Knes
Three clues to the origin of Ryugu
However, the first Ryugu data was a bit unexpected and led to some hypotheses to explain it. The asteroid does indeed have a tip shape, which is well explained if it took on an equilibrium shape in response to its own rapid rotation. It only remained to explain this rapid rotation.
To also understand its form of balance, it is necessary to know that it has been found that Ryugu can be seen as a pile of rubble, composed of small pieces of stone and materials.agglutinated not a single monolithic rock. One way to explain this is to postulate that these are actually fragments formed by the collision of two asteroids, which then had to slowly join under the influence of their own gravity (the size of Ryugu is approximately 920 meters).
According to other data provided by the mission, the small celestial body is surprisingly rich in organic matter.
All of these puzzle pieces about Ryugu’s identity and origins (162173) have been put together in an entirely new way by a research team led by Hitoshi Miura from Nagoya City Universityin Japan, in an open access article in.
Planetologists have built a new model that better explains all of Ryugu’s observations, and have come to the astonishing conclusion that it is a dead comet, that is, what could be left of such an object on Earth.periodic, when its repeated passages close to the Sun have almost exhausted the supply of volatiles – mainly water ice.
Script developed withHitoshi Miura and his colleagues Eizo Nakamura and Tak Kunihiro of Okayama University, Japan are conceptually simple. If Ryugu really was a comet, then we can compare it to water ice with chocolate chips melting on the surface and evaporating several times. The nuggets will settle and eventually concentrate and collect at the bottom of the container containing the original mixture.
Formed outside the orbitin Originally about 4.5 billion years ago, the comet must have been so famous intergrown blocks of various sizes with ice encapsulating everything.
Evaporating, the comet decreases in size, which changes its momentum.as in the case of a figure skater bringing her hands together. Preservation lead her to her accelerate as its size decreases.
The researchers’ model then explains this top shape caused by the calculated rotation speed. across fromand we also understand why, since it was originally a comet formed in cold regions rich in volatile organic matter, Ryugu appears to be much more carbonaceous than other asteroids studied from Earth using spectroscopy.
According to a statement from Nagoya University accompanying a published paper, the top and pile objectswith a high organic content, such as Ryugu and Bennu (mission target ) will be comet-asteroid (CAT) transition objects. ” CATs are small objects that were once active comets but have become extinct and are apparently indistinguishable from asteroids. “Hitoshi Miura explains, who adds:” because of their similarities to comets and asteroids, CATs could provide new information about our solar system. “.