Researchers have crafted an innovative model to elucidate how enormous planets, like Jupiter, come into being, offering improved insights into planetary formation processes and enhancing our comprehension of various planetary systems.
A team of LMU researchers has created a groundbreaking model to clarify the formation of massive planets such as Jupiter, which provides deeper understanding into the mechanisms of planet formation and could broaden our perspective on planetary systems.
Our solar system is our closest cosmic environment, and we are quite familiar with it. It features the Sun at its core, rocky planets like Mercury, Venus, Earth, and Mars, followed by the asteroid belt, gas giants Jupiter and Saturn, ice giants Uranus and Neptune, and finally the Kuiper belt filled with comets. However, how extensively do we truly understand our celestial home? Earlier models suggested that giant planets form by the collision and accumulation of asteroid-like bodies known as planetesimals, with gas gradually accumulating over millions of years. Yet, these models fail to account for gas giants located far from their stars or the emergence of Uranus and Neptune.
From dust grain to a colossal planet
A team of astrophysicists from LMU, the ORIGINS cluster, and MPS has established the first comprehensive model incorporating all essential physical processes involved in planet formation. Their research illustrates that disturbances in protoplanetary disks, referred to as substructures, can catalyze the swift formation of several gas giants. The findings align perfectly with the latest scientific observations, suggesting that the formation of giant planets may proceed more efficiently and rapidly than previously anticipated.
Through their model, the researchers illustrate how tiny, millimeter-sized dust particles consolidate due to aerodynamic effects within the turbulent gas disk. This initial disruption in the disk captures dust, preventing it from drifting towards the star. This concentration of material significantly enhances the growth of planets, as an abundance of “building material” becomes available within a relatively small area, creating ideal conditions for planet formation.
“Once a planet reaches a certain size to affect the gas disk, it causes renewed dust accumulation further out in the disk,” says Til Birnstiel, a Professor of Theoretical Astrophysics at LMU and a member of the ORIGINS Cluster of Excellence. “This dynamic resembles a sheepdog herding its flock, as the planet drives the dust toward regions beyond its orbit.” This cycle initiates again, enabling the potential formation of another giant planet. “For the first time, a simulation has accurately tracked the transformation of tiny dust into massive planets,” notes Tommy Chi Ho Lau, the primary author of the study and a doctoral student at LMU.
Diversity of gas giants in our solar system and beyond
In our solar system, gas giants range from approximately 5 astronomical units (AU) (Jupiter) to about 30 AU (Neptune) away from the Sun. For reference, Earth is situated roughly 150 million kilometers from the Sun, which equals 1 AU.
The study reveals that in other planetary systems, disturbances can initiate formation processes at much larger distances while still maintaining a rapid pace. Observations by the ALMA radio observatory have frequently identified gas giants residing in young disks over 200 AU away. Additionally, the model elucidates why our solar system seemingly ceased additional planet formation after Neptune: all the available material was simply depleted.
The findings align with current observations of young planetary systems that exhibit distinct substructures in their disks, which are critical to planet formation. This study suggests that the creation of giant and gas planets operates with greater efficiency and speed than previously considered. These fresh insights could refine our understanding of the origins and evolution of the giant planets within our solar system and clarify the variability seen in other planetary systems.
