Astrophysics, discoveries of stars that eat planets: in chemistry the evidence

We are used since elementary school to think that our Solar System, formed by a star around which the planets rotate, is the only possible model in the whole galaxy. In fact, it has already been demonstrated for some time that two-thirds of the stars observed are brought together to form multiple systems. Of these, most of them are binary: two incandescent bodies which, while making their own elliptical orbit, exert such a gravitational attraction between them as to create a common point, a center of gravity of rotation.

Different compositions

And it is precisely by studying these particular systems that astrophysicists have come across one of the greatest contradictions: stars are composed of the same material, and for this reason it is logical to expect that they have an identical chemical composition. It is not so. Recent studies have revealed how, in fact, these are different. The theory does not match the results obtained. Seeking a solution to this apparent paradox, a new study published in Nature Astronomy offers a possible solution. The starting hypotheses were two: either the stars have differences since their proto-stellar condition (which would compromise all the knowledge we have on the subject) or some external elements have influenced their formation.

Planetary cannibalization

Examining 107 binary systems from the telescope of the Southern European Observatory in La Silla, Chile, Dr. Lorenzo Spina of the National Institute of Astrophysics (INAF) in Padua and his colleagues collected data that “represent a generational breakthrough in stellar astrophysics” . It would be precisely those so complex motions to bring a planet so close to one of the two stars that it would end up being swallowed up. This is the phenomenon of “planetary cannibalization”: an event that did not occur in our system precisely because, as Spina explains, being only the Sun “it has preserved its planets on ordered and almost circular orbits”. The first author of the article is certain: “The observed anomalies are the direct consequence of the cannibalization of planets. Our study opens up the possibility of using information on the chemical composition of stars to identify those that are most likely to host twins from our Solar System ”.