Researchers from Queen Mary University of London have shed new light on how wandering planets come to be. The findings are shared through scientific publications on arXiv.
Wandering planets, also called rogue planets, are objects with planetary mass that drift through space without being bound to a star. They are hard to detect and remain one of the more enigmatic topics in planetary science.
It is understood that rogue planets can originate inside the disks around newborn stars or arise from vast clouds of gas and dust. Some planets break away from their stellar orbits and end up roaming interstellar space under certain circumstances.
In the latest work, researchers carried out a range of simulations to pinpoint the conditions that cause a planet to escape its orbit and wander freely in the galaxy.
Simulation results indicate that the primary source of drifting planets is tied to binary star systems, where a planet orbits two stars. During the life of such a system, between two and seven Earth‑mass planets can be expelled into space. When the bodies involved are giants, about a hundred times heavier than Earth, the likelihood of ejection drops significantly, to roughly six tenths of a percent.
The simulations examined several factors: the initial mass of the protoplanetary disk, the external environment, and the level of turbulence within the disk. Each scenario ran for ten million years, a span long enough for the system to fully form and undergo dynamic evolution.
Looking ahead, astronomers aim to identify the star types that most frequently shed planets into interstellar space and to understand how these rogue bodies populate our galaxy.
Earlier work also explored planets orbiting stars that have cooled and died, revealing new insights into the late stages of planetary systems.