An international team of astronomers, with pivotal contributions from Leiden University in the Netherlands, has shared new insights into a dramatic collision between two enormous exoplanets. Each planet is estimated to range from three to ten times the size of Earth, and the results are detailed in a leading science journal. This research adds a remarkable chapter to the study of planetary mergers that occur far from our solar system, expanding our sense of what is possible in planetary evolution across the cosmos.
The discovery arose from a meticulous examination of a young star, about 300 million years old, whose properties echo certain solar similarities. For a period of roughly 1000 days, its observed light remained unusually consistent. Then, after around 2.5 years, a prolonged eclipse swept across the stellar disk, dimming the star for approximately 500 days. The sequence suggested something extraordinary in the surrounding material rather than a simple, distant companion crossing the star’s face.
Researchers interpreted the eclipse as the signature of a vast cloud composed of gas and dust that envelops the star. The most plausible explanation points to a colossal collision between two sizeable planets, one of which possessed a substantial ice component. The impact would have heated the bodies, leading to partial melting and substantial disruption. What remained were exposed cores, now shrouded by vapor and debris that formed a dense, evolving veil around the system. This interpretation aligns with models of extreme energetic events capable of reshaping planetary bodies on a scale rarely observed in nearby stellar neighborhoods.
After the collision, the hot, dusty remnant persisted under gravity, continuing to orbit the star as a bound structure. Over time, this material grew opaque to distant observers, effectively occluding the star from Earth-based measurements. The evolving debris cloud acts as both a historical record of a violent past and a dynamic laboratory for studying how planetary remnants interact with their stellar environment and with each other as they settle into new configurations.
Looking ahead, researchers aim to study this system with greater precision using the James Webb Space Telescope. The goal is to obtain higher-resolution data that can sharpen models of the collision mechanism, the resulting debris cloud, and the long-term evolution of the surrounding material. Future observations will help determine how such debris disks dissipate, how cores and clumps migrate within the cloud, and what this implies for the potential formation paths of moons and other satellites in distant planetary systems. The work also invites comparisons with other systems where violent formation channels may play a role, offering a broader context for interpreting similar signals in the galaxy and beyond, all while grounding these ideas in robust observational evidence and theoretical frameworks. [Citation: Observational astronomy reports, Leiden University consortium; corroborating analyses from multiple independent teams]