A new study reveals a planetary system in the Milky Way traveling at an astonishing speed of 541 kilometers per second, making it the fastest known system. This discovery challenges existing theories about the survivability of such systems.
Lead author Sean Terry, an astrophysicist at the University of Maryland, expressed surprise at the high velocity, which was determined through observations of a red dwarf star located 25,000 light-years from Earth. The system was initially identified during a microlensing event in 2011, where the star's light was warped by its gravitational influence.
Further observations in 2021 from the W. M. Keck Observatory indicated that the system's known planet is likely a gas giant, approximately 29 times the mass of Earth, orbiting at a distance similar to that between Venus and Earth. There may also be additional, unseen planets.
The star's extreme speed suggests it may be a hypervelocity star, a rare class accelerated by interactions with other stars or gravitational slingshots from supermassive black holes. This system's speed is significant, as hypervelocity stars typically exceed 500 kilometers per second.
Jessie Christiansen from NASA's Exoplanet Science Institute noted that this discovery provides insights into the types of planetary systems that may exist in the dense regions of the galaxy's center, raising questions about the impact of such environments on planet formation.
Although the known planet orbits outside the habitable zone of its star, its existence indicates that planets can endure the chaotic conditions associated with high-velocity stars, potentially opening new avenues for research into the origin and evolution of planets in extreme environments.