(ORDO NEWS) — This did not allow the Earth to grow to the size of a “super-earth”.
Before Earth and other planets appeared in the solar system, the sun may have been surrounded by giant rings of dust, similar to those of Saturn, according to new research.
Scientists believe these dust rings may have prevented our planet from becoming a “super-earth” – a type of planet about twice the size of Earth and 10 times its mass.
Astronomers have previously discovered “super-Earths” near about 30 percent of the sun-like stars in our Galaxy.
To start this study, astrophysicist from Rice University in Houston Andre Isidor prompted the question: “why, if” super-Earths “are a common phenomenon for stellar systems like ours, they are not in the solar system?”
To find out, Isidor and his colleagues created a computer simulation model of the formation of the solar system, which emerged from a cloud of dust and gas known as the solar nebula.
Simulations showed that the newborn Sun must have been surrounded by areas of high pressure of gas and dust. These high-pressure areas likely arose when particles were pushed towards the Sun by its strong gravitational pull, heated up, and released large amounts of vaporized gas.
There were probably three different areas, called “sublimation lines”, where solids vaporized into a gas. On the line closest to the Sun, or in the hottest zone, the solid silicate turned to gas, on the middle line, the ice also heated enough to turn into gas, and on the farthest line, carbon monoxide turned into gas.
Simulations have shown that particulate matter, such as dust, crashed into these “irregularities” and accumulated there.
“The pressure jump effect is that it collects dust particles, which is why we see rings,” – Andrea Isella, study co-author.
If these pressure surges did not exist, the Sun would quickly absorb the particles, leaving no seeds for the growth of the planets. “It takes something to stop them, to give them time to turn into planets,” explains Isella.
With age, the gas and dust surrounding the Sun has cooled, and the sublimation lines have moved closer to the Sun. This process allowed dust to accumulate in planetesimals, or seeds of asteroid-sized planets, which could then come together to form planets.
According to simulations, the closest ring to the Sun formed the planets of the inner solar system – Mercury, Venus, Earth, and Mars.
The middle ring eventually became the planets of the outer solar system, and the outermost ring formed comets, asteroids, and other small bodies in the Kuiper belt, an area beyond the orbit of Neptune.
The researchers also found that if they simulated the slow formation of the middle ring, then “super-earths” could form in the solar system.
“By the time the pressure surge occurred in these cases, a large mass had already invaded the internal system and was available to create super-earths. Thus, the time when this average pressure jump was formed could be a key aspect of the solar system, ”concludes Isidor.
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