Asteroids under the influence of Sun radiation are capable, being gradually untwisted, to halve and turn to smaller two asteroids which then can and remain connected “duet” or disperse in space.
The international group of scientists under the direction of Petr Pravec from Astronomical institute of Czech has studied 35 so-called steams of the asteroids consisting of two heavenly bodies which move on similar orbits round the Sun and for the last one million years approached to distance in some kilometers with very low relative speeds. Such objects in 2008 were opened by one of coauthors of work David Vokrouhlicky from Karlov of university in Prague, however till now the mechanism of their occurrence remained not clear.
“It, probably, the clearest and evident certificate of that asteroids – not simply big stones in orbits round the Sun, not changing the form eventually. On the contrary, it is the small worlds which” with the years “can constantly change, sometimes” generating “smaller asteroids, then beginning own life”, – the coauthor of work Daniel Scheeres has told from university of the State of Colorado in Bouldere, whose words are resulted by the university press-service.
Under the pressure of a sunlight the asteroid is gradually untwisted, and at sufficient speed of rotation it can break up into others two. These asteroids start to rotate the friend round the friend, forming so-called double asteroids. However, according to authors of the work, many such systems can break up in due course and then on a place of one asteroid there are two.
Having measured relative brightness of the pairs investigated by them, scientists by means of photometric methods have established speed of their rotation and the size which made from one to ten kilometers. They have found out that for all pairs the same parity was observed: the size of a smaller component always made less greater.
Thus, as it is marked in article, the mechanism of formation of double asteroids which then can “run up”, doesn’t depend on their mineralogical properties: thus asteroids of both key types, coaly and silicate on which it is necessary about 90 % of all known asteroids, most likely, can “share”.
Sunlight, falling on an asteroid in the size less than 10 kilometers in a diameter, can change for millions years its rotation is such slowed down version of reaction of a mill on a wind. It forces small asteroids to rotate faster while they “do not break up”. Easy “to deduce from itself” these steams of asteroids