2021-10-17

The study found a mysterious gap in the protoplanetary disk of the solar system

By yqqlm yqqlm

The study found a mysterious gap in the protoplanetary disk of the solar system

a new analysis of ancient meteorites by scientists at the Massachusetts Institute of Technology (MIT) and elsewhere shows that about 4.567 billion years ago, there was a mysterious gap in the disk near where the asteroid belt is today

the team’s achievements were published in science advances on October 15, 2021, providing direct evidence for this gap

“over the past decade, observations have shown that cavities, voids and rings are very common in the disks around other young stars,” said Benjamin Weiss, Professor of planetary science at EAPs, Department of earth, atmosphere and Planetary Sciences (EAPs), Massachusetts Institute of technology. “These are important but unknown signs of the physical process of gas and dust transforming into young sun and planets.”

similarly, the reason for this gap in our own solar system remains a mystery. One possibility is that Jupiter may be an influence. When the gas giant takes shape, its huge gravity may push gas and dust to the periphery and leave a gap in the developing disk

another explanation may be related to the wind appearing on the surface of the disc. Early planetary systems were dominated by strong magnetic fields. When these magnetic fields interact with rotating gas and dust disks, they can produce strong wind, which is enough to blow material out and leave a gap in the disk

regardless of its origin, the gap in the early solar system is likely to be a cosmic boundary, so that the matter on both sides cannot interact. This physical separation may shape the composition of the planets in the solar system. For example, on the inner side of the gap, gas and dust condense into land planets – including earth and Mars, while the gas and dust classified on the far side of the gap form in colder areas, such as Jupiter and its adjacent gas giant planets

“crossing this gap is quite difficult. A planet requires a lot of external torque and power,” said cau ê borlina, the main author of the paper and a graduate student of EAPs. “Therefore, this provides evidence that the formation of our planet is limited to a specific region of the early solar system.”

in the past decade, Scientists observed a strange split in the composition of meteorites entering the earth. These space rocks were originally formed at different times and places when the solar system was formed. Those meteorites that have been analyzed show one of two isotopic combinations. Few meteorites have been found to show two isotopes at the same time — a difficult problem called “isotope dichotomy”

scientists suggest that this dichotomy may be caused by a gap in the disk of the early solar system, but this gap has not been directly confirmed

Weiss’s research team hopes to find signs of ancient magnetic field through the analysis of meteorites. When a young planetary system takes shape, it carries a magnetic field whose strength and direction can be changed according to various processes in the evolving disk. When ancient dust gathered into particles called cartilage, the electrons in the cartilage particles were consistent with the magnetic field they formed

cartilage particles can be smaller than the diameter of human hair and are found in today’s meteorites. Weiss’s team specializes in measuring cartilage particles to determine the ancient magnetic field they originally formed

in previous work, the team analyzed one sample of meteorites from two isotopic groups, known as non carbonaceous meteorites. These rocks are thought to have originated in a “container” or relatively close to the sun in the early solar system. Weiss’s team previously found ancient magnetic fields in samples from this region near the sun

in their new study, researchers want to know whether the magnetic field will appear in the “carbonaceous” meteorites of the second group of isotopes. From their isotopic composition, they are considered to have originated further away from the solar system

they analyzed the cartilage particles of two carbonaceous meteorites found in Antarctica, each about 100 microns in size. Using a superconducting quantum interference device, a high-precision microscope in squid Weiss laboratory, the research team determined the original and ancient magnetic fields of each cartilage particle

surprisingly, they found that their magnetic field strength was closer to that of non carbonaceous meteorites than they had previously measured. As young planetary systems are forming, scientists predict that the strength of the magnetic field should decrease with distance from the sun

in contrast, borlina and his colleagues found that the cartilage mine in the distance has a stronger magnetic field, about 100 micro Tesla, while in the cartilage mine in the near, the magnetic field is 50 micro Tesla. As a reference, the earth’s magnetic field today is about 50 micro Tesla

the magnetic field of a planetary system is a measure of its accretion rate, or the amount of gas and dust it can absorb to its center in a period of time. According to the magnetic field of the carbonaceous cartilage column, the outer region of the solar system must have a lot more mass than the inner region

by using the model to simulate various situations, the research team concluded that the most likely explanation for the mismatch of accretion rates is that there is a gap between the inner and outer regions, which may reduce the amount of gas and dust flowing from the outer regions to the sun

borlina said: “gaps are very common in protoplanetary systems, and we now show that there is one in our own solar system. This gives the answer to the strange dichotomy we see in meteorites, and also provides evidence that gaps affect the composition of planets.”