What the Solar System looked like 4.5 billion years ago: astronomers have made an unexpected discovery (photos).

To understand what the newly formed Solar System looked like 4.5 billion years ago, one must examine the protoplanetary disks surrounding other stars where planets are forming. In the distant past, the Sun was also surrounded by a disk of gas and dust from which all 8 planets of the Solar System emerged. Astronomers have utilized radio telescopes and optical telescopes to study binary protoplanetary disks that encircle binary stars. Special attention has been drawn to the binary star DF Tau due to its unusual characteristics. One might assume that protoplanetary disks around binary stars should be similar, as they are formed from the same material as the stars themselves. However, a study published on the preprint server arXiv revealed remarkable differences between them, as reported by Universe Today.

The binary star DF Tau is located just over 400 light-years away and consists of two young stars of equal mass. It is likely that both stars formed from the same molecular gas cloud, yet their protoplanetary disks do not resemble each other.

The brighter star in the binary system has an active inner region of its protoplanetary disk, while the second star's inner region has nearly disappeared. Astronomers are currently unable to determine what exactly occurred and believe that some unknown processes are involved.

In such protoplanetary disks, matter clumps together under the influence of gravity, leading to the formation of planets. The planet formation process ultimately results in the dispersal of the protoplanetary disk. However, in this case, it is unclear whether planets exist in the disk around one of the stars in the DF Tau system. The gravity of the star may also not have been sufficient to disperse the inner part of the disk.

The discovery of protoplanetary disks around other stars provides insight into how the Solar System appeared in its early stages and how planets began to form within it. However, binary protoplanetary disks demonstrate a more complex process of planet formation around binary stars.

Astronomers need to understand the processes behind the dispersion of the inner protoplanetary disk. Could it be related to faster planet formation in one disk? It is essential to comprehend why two identical stars in a binary system can have different protoplanetary disks.

Scientists speculate that the two protoplanetary disks have different densities, or perhaps there is a substellar object near the second star that is creating a gap in the protoplanetary disk as it moves. It is possible that young stars can influence their disks differently, leading to their rapid disappearance.

The binary star DF Tau was not the only system studied by astronomers. This data helps to better understand how protoplanetary disks evolve not only around single stars but also around binary stars. Their evolution directly impacts planet development.