A stellar passage that occurred millions of years ago may still be redirecting comets toward Earth today, new research suggests. Planetary Science Institute Senior Scientist Nathan Kaib and collaborator Sean Raymond from the Universite de Bordeaux found that a recent flyby of a nearby star perturbed Oort cloud objects, sending a cascade of comets into the inner solar system.
The Gaia mission's precise stellar motion data enabled the team to model these ancient gravitational interactions. The findings indicate a single stellar encounter can have long-lasting consequences, reshaping the architecture of cometary reservoirs over cosmic timescales.
Kaib and Raymond presented their work at the American Astronomical Society Division on Dynamical Astronomy meeting. The research highlights how stellar flybys, once thought to be rare and transient events, can leave enduring imprints on the solar system's dynamics.
These results suggest that the current rate of long-period comets entering the inner system may be partially influenced by a flyby that occurred millions of years ago. Future observations could help pinpoint the specific star responsible and refine models of comet behavior.
Experts caution that while the Gaia data is robust, the exact timing and magnitude of the flyby's effects remain uncertain without direct paleo-cometary records.