The formation of planets is not fully understood, but it is believed that gravity is not the only thing that pulls matter. Magnetism in the protoplanetary disk also would play a role in the formation of small and large bodies.
Meteorite samples reveal this idea for the inner Solar System, but we had no idea if the outer Solar System was affected by magnetism; now, with the help of asteroid Ryugu, we found out.
Asteroid Ryugu is strange – maybe even an extinct comet. It was visited by the Japanese Hayabusa-2 mission, which collected samples. The asteroid’s host body underwent catastrophic collisions and formed much farther from the Sun before migrating inward.
In the collected grains of material, frozen in time, was evidence of the magnetic field from the time of formation.
The new analysis estimates that it was on the order of 15 microteslas, less than a third of our planet’s magnetic field today and much weaker than the magnetic field in the protoplanetary nebula inside the solar system where Earth, Mars, Venus and Mercury, which could have been up to 200 microteslas, he writes IFLScience.
The formation of planets is not fully understood
Despite its relative weakness, researchers believe it was enough to affect the formation of bodies at distances more than seven times the Earth-Sun distance. This includes Jupiter, Saturn, Uranus and Neptune, as well as countless comets, asteroids and small worlds.
“We show that everywhere we look now, there was some kind of magnetic field that was responsible for bringing mass to where the Sun and the planets were forming,” said Benjamin Weiss, co-author of the study and the Robert R. Shrock Professor of Science. of Earth and Planetary Sciences at MIT. “This now also applies to planets in the outer Solar System,” Weiss added.
The Sun formed from a collapsing cloud of interstellar gas. Part of that cloud, following the formation of the Sun, ended up in a disk.
This swirling protoplanetary disk was filled with ionized gas that interacted with the nascent star through important magnetic interactions. Gravity, magnetism, and the angular momentum of the rotating field led to the birth of the planets shortly thereafter.
Astronomers are waiting for analysis of the magnetic field on asteroid Bennu as well
“This nebular field disappeared about 3-4 million years after the formation of the Solar System, and we are fascinated by how it played a role in early planetary formation,” explained lead author Elias Mansbach.
The team also looked at meteorites believed to be from the distant solar system and found weaker measurements for the magnetic field, although generally consistent with an upper limit of 15 microteslas.
The team is looking forward to analyzing the magnetic field on asteroid Bennu. A large sample of the asteroid was collected by NASA’s OSIRIS-REx mission, and it will be very interesting to learn what information we can get about what this primordial magnetic field (at least for the Solar System) was like where Bennu formed.
The study is published in the journal AGU Advances.
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Source: www.descopera.ro
