Storms are the origin of planet formation

New research shows that volatility plays an important role in creating the right conditions for planet formation. This study, published in the Astrophysical Journal, challenges the usual theory of planet formation.

A sequence of images shows fluctuating forces (Coriolis impact and vertical displacement) disturbing layers of dust and gas surrounding young stars. The image depicts a two-dimensional surface by simulation of Joseph Barranco. Deep red indicates a lot of dust. Dark green indicates pure air. Simulation based on dust and gas and distance to mother. The interval between photos is 3.4 years. (Photo: Joseph Barranco)
Using simulations of three-dimensional gas and dust surrounding young stars, the study demonstrates that volatility is a significant obstacle to gravity instability, the process scientists have used since 1970. to explain the early stage of planet formation.

Gravity instability causes dust to lie in planetary disks around newly formed stars. Previous thoughts suggest that dust will gradually become thinner and denser until it reaches a critical point and concentrates into kilometer-sized blocks. These blocks then collide with each other and form the planet. However, research by Professor Jospeh Barranco of San Francisco State University showed that the fluctuating forces keep the gas and dust swirling and prevent them from becoming thin and dense layers so that the instability of gravity appears. .

Barranco said: 'These results go against the previous theory of planet formation. Scientists have long used the theory of gravity instability to explain how millimeter-sized particles focus into kilometer-sized blocks. However, these new simulations open up another research direction. It is possible that big storms, like windstorms seen on Earth and Jupiter, are clues to how small dust particles gather to become kilometer-sized blocks. '

Previous studies used two-dimensional models to simulate the layers of dust and gas that revolve around young stars, so they ignore a very important force to create fluctuations: Coriolis impact. Using a three-dimensional model, Barranco investigated the Coriolis effect, which is the mechanism of formation of tornadoes, cyclones on Earth, and vertical displacement. Vertical displacement occurs because fast moving layers of dust gather together with the slow moving gas above and below.The difference in speed between gas and dust creates waves, similar to the wind blowing on the surface of the water.

Barranco said: 'What happens to the dust and after the change is still an unanswered question. It is very likely that, at the center of the storms, dust gathers and clogs, opening the process of planet formation '.

Joseph A. Barranco is a professor of physics at San Francisco State University.