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Perhaps many do not know that Brian May , the mythical guitarist of the group Queen , is also an astrophysicist very active, and who for many years devoted large efforts to understanding better the nature of the thousands of comets and asteroids that circulate continuously around the Solar System .
Now, May has participated, along with other astrophysicists, in a study designed to investigate the mysterious similarities between several asteroids different and already explored by space probes. The idea is that many of them could be fragments of other bodies much larger, fragmented by violent collisions. The work has just been published in Nature Communications.
In his study, Brian May and the rest of the researchers highlight the fact that both the asteroid Bennu, of 525 meters in diameter and has been visited recently by the probe OSIRIS-REX of NASA, as the asteroid Ryugu, 1 km in diameter and closely studied by the probe japanese Hayabusa2, they have almost exactly the same form of spinning top and share, in addition, a density very similar. However, both contain different amounts of water. is Ryugu , in fact, has a lot less Bennu , and that has hindered, until now, that both have a common origin.
“The shapes of asteroids and their level of hydration,” explains May – can serve as tracers of their origin and history”.
Precisely, the participation of Brian May in this study arose out of their investigation of asteroids, including the work on the scientific equipment of Hayabusa2 and OSIRIS-REx and as a member of the Advisory Board of the project of Modeling of Near-Earth Objects and Loads for the Protection (NEO-MAPP), funded by The program H2020 of the European Commission.
Led by Patrick Michel , director of Research at the Observatory of the French CNRS at the cote d’azur, the authors of the article believe that this research may also be relevant to the mission of planetary defense Hera, the European Space Agency and of which Michel is the scientific director. Hera, in effect, you will explore the binary system of asteroids Didymos after the deflection orbit of the smaller of the two bodies carried out by the mission DART , NASA.
“The shape of spinning top of Bennu and Ryugu -explains Michel-, which includes a bulging equatorial pronounced, is shared by many other asteroids, including the largest of the two asteorides of the system Didymos , of 780 meters. The main hypothesis is that a high rate of rotation means that, over time, the centrifugal force to change the shape of those asteroids, to the extent that the material flows from the poles toward the equator”.
“In the case of Didymos -continues the researcher – that could explain where it comes from its small moon Didymos, which could form from the material that was released to the equator of the body increased due to the rapid rotation. However, in the case of Bennu and Ryugu there is a problem: the close observation conducted by the two missions that were studied has revealed large craters on their crests equatorial, suggesting that these bulges formed early in the history of such asteroids”.
a Recreation of the asteroid binary Didymos along with its small moon, Didymos TO – THAT To Ron Ballouz , Laboratory Lunar and Planetary University of Arizona and who also signs the study, these findings raise an important question: “what Are those properties (shape of the asteroid, density, hydration levels more or less high, etc.) a consequence of the natural evolution of such objects or rather the immediate result of their training process?”.
“take a look” back in time, the researchers conducted several computer simulations of asteroids of about 100 km that had been fragmented due to collisions, thus releasing many fragments, which were transformed with the time into smaller objects. It is believed, in fact, that is the mechanism by which have formed the greater part of the asteroids over 200 meters .
“The simulations, says Michel – they were extremely demanding from the computational point of view, and it took several months in lcompletarse. The most challenging part was to simulate the process of reaccumulation, which included a detailed coding for the contact of particles, sliding and friction by court. We also observed the level of heating of the fragments after impact, determining your level of hydration”.
In this way, the researchers realized that, while the process of reaccumulation led to a wide variety of shapes, there is a trend towards the spinning top, as the material of aggregation tends to accumulate in forms spheroids. “These spheroids,” continues Michel – can be accelerated by the effect of YORP (a gradual warming caused by the light of the Sun, which received its name from its discoverers, Yarkovsky, o’keeffe, Radzievskil and Paddack ) to form a bulge equatorial on a rapid time scale in terms of asteroids, of less than a million years ago, which explains what we see in Bennu and Ryugu”.
The image shows the extraordinary resemblance between the asteroid Bennu, studied by the mission OSIRIS-REX, NASA, and Ryugu, visited by the probe japanese Hayabusa2 – ESAUn common origin
But the scientists also discovered another thing. The final levels of hydration of the asteroids can vary greatly between those that were formed from the fragments of the main body. In that sense, Brian May worked with Claudia Manzoni , of the London Stereoscopic Company, to produce images stereographic 3D of the immediate consequences of the impacts, revealing that the individual fragments display a wide diversity in their levels of warming and, therefore, hydration.
“During a collision -explains May – it is possible to form an aggregate, such as Bennu, which experienced little calentamieto by impact, and the other as Ryugu, made of warmer material”.
In the words of Michel, “the result is that Bennu and Ryugu could form part of the same family of asteroids , and have the same ‘father’ despite the fact that your hydration levels are now very different. We know that they come from the same region of the asteroid belt, which increases that possibility, even though only we will know with certainty when we can analyze samples of such asteroids that will be returned to the Earth for Hayabusa2 and OSIRIS-REX”.
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