(ORDO NEWS) — Scientists at the California Institute of Technology and the Côte d’Azur Observatory have proposed a new hypothesis for the formation of planets that explains the emergence of super-Earths – a class of exoplanets that are several times more massive than Earth.
According to Konstantin Batygin, one of the authors of the study, observations of exoplanets over the past decade have shown that the standard theory of planet formation needs to be revised.
It should explain not only the formation of the solar system’s rocky planets, but also the origin of systems in which super-Earth planets turn out to be similar to each other in terms of distance between orbits, size, mass and other characteristics.
According to one of the researchers’ hypotheses, the formation of planets in the solar system occurred in two separate rings of the protoplanetary disk.
Small rocky planets (Mercury, Venus, Earth and Mars) formed in the inner ring, and massive ice giants formed in the outer ring, two of which turned into Jupiter and Saturn.
Super-Earths are not found in the solar system, although some have thick hydrogen atmospheres, making them look like giant gas planets.
The new model for the emergence of super-Earths is based on a work published in 2020 by Batygin and Alessandro Morbidelli, in which scientists explained the formation of the four largest satellites of Jupiter – Io, Europa, Ganymede and Callisto, collectively known as the Galilean satellites.
A decrement disk is formed around the gas planet, from which the outflow of matter occurs, but at the same time ice dust accumulates in it. In this disk, celestial bodies are formed, which leave it as soon as they reach a sufficient size.
In the case of an entire planetary system, hard rock material is concentrated in a narrow ring of the disk, called the silicate sublimation line, where hard pebble particles form.
This section of the disk functions as a “factory” capable of producing several rocky planets of the same size. As the planet grows, interacting with the matter of the disk, it migrates closer to the star.
If the ring contains a lot of mass, the planets grow until they migrate away from it, resulting in a system of similar super-Earths.
If the ring has a small mass, it forms a system that is more like the terrestrial planets of the solar system.
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