We are all living things that started from a single cell. The small fertilized egg formed by the meeting of an egg and sperm is implanted, grows gradually, and comes out into the world 10 months later.
It is very small before being born like this, but it is the same with planets such as Earth and Jupiter that gradually grow and become a full-fledged adult. The earth we live on was formed from tiny pieces of material gathered in a protoplanetary disk, a ring of gas and dust around the sun, when it was still a baby star.
Of course, it is not possible to directly confirm this appearance going back 4.6 billion years, but scientists have confirmed the planetary hypothesis by identifying protoplanetary disks around many baby stars. Of course, it is not easy to observe baby stars formed in gas and dust-filled nebulae, so capturing small protoplanets that are born in nearby protoplanetary disks is a formidable task for scientists.
A research team from Monash University in Australia discovered a tiny embryo-like protoplanet growing around one of the well-known protoplanetary disks, HD169142. HD169142 is not close to Earth, but it is relatively easy to observe because the protoplanetary disk is at a downward-looking angle when viewed from us.
Through observations, the research team discovered a ring-like gap in the orbit of Neptune in the solar system where the material of the protoplanetary disk thins out. These gaps are usually thought to be the result of material being absorbed by the growing protoplanet. On one side of the gap, the research team identified a small, fetal-like mass seen by ultrasound. However, due to the low resolution, it was difficult to distinguish whether it was a real planet or a ball of gas passing by.
Therefore, over several years, the research team observed whether the mass had a planetary Kepler motion. As a result, the clump is not only orbiting the baby star, but also exerting a gravitational influence on the surrounding rings.
According to the team’s simulation model, this protoplanet is not a very small embryo, but is already a planet as large as Jupiter and continues to grow while absorbing materials from its surroundings. From the ultrasound image, it looks like a small nursery that has just been implanted, but in reality it is a considerably grown fetus, entering the second half of pregnancy.
When HD169142, now a baby star, reaches the point of becoming a normal star in the distant future, it releases strong energy and pushes out the surrounding gas, causing the protoplanetary disk to dissipate and the planet growing in it to emerge, forming a planetary system. Of course, it is presumed that the planet currently being formed is probably not one.
This process is a fleeting moment for stars and planets that live for eons, but each process spans millions of years, making it impossible to observe all processes from a single star. Instead, scientists study the process of star and planet formation by observing baby stars and protoplanetary disks in different stages.
And as telescopes and observation equipment develop, more detailed information is pouring in. HD169142 is an important observation target, and follow-up observations and research results are expected.
Gordon Jung Science Columnist jjy0501@naver.com
