530 light years away is the young star AB Aurigae. A couple of years ago, astronomers discovered a curious pattern of spiral disturbances in the protoplanetary disk that surrounds it. Now, a new study seems to have found an answer to the characteristic: we are facing a planet in formation, and if so, the first direct evidence of the formation of a “baby” planet.
In the researchers’ work, published in Astronomy & Astrophysics , the planet is compared to a boat on a lake. As it spins, it leaves a trail on the gas disk. But the planet is also capturing some of that gas, creating a spiral pattern, and in particular a strange twist. These peculiar gas chains that reach the same region point to the presence of an invisible planet. As they tell in their publication:
At the initial stage of planet formation, hydrodynamic simulations indicate that the accretion process generates an internal and external spiral pattern at the planet site due to Lindblad resonances induced by disk-planet interactions. While this crucial step is well documented by theoretical work, observational evidence is rare and not entirely conclusive.
In this way, they have obtained new historical images of the process in action. If it were there, the planet would be as far from AB Aurigae as Neptune from the Sun, approximately 4.5 billion km. According to researcher Anthony Boccaletti, lead author of the study:
We need to observe very young systems to really capture the moment planets form. Thousands of exoplanets have been identified so far, but little is known about how they form.
Thanks to the new observations, both the inner spiral and the spin were visible, which is very important, as they corroborate some current ideas about how planets could be born. For co-author Anne Dutrey:
The twist is expected from some theoretical models of planet formation. It corresponds to the connection of two spirals, one that coils inward from the planet’s orbit and the other that expands outward, which meet at the planet’s location. They allow gas and dust from the disk to accumulate on the forming planet and make it grow.
The researchers say that the gigantic ESO Telescope that is being built in Chile at this time will have the ability to see the system even more in depth. If so, you will be able to confirm whether the “baby” planet is actually coming into existence.