A rare “time-critical” decision has been made to study the true size of the potentially hazardous asteroid 2024 YR4 using the powerful James Webb Space Telescope (JWST). With a roughly 2.3% chance of impacting Earth in 2032, astronomers have been granted emergency use of JWST to observe the asteroid in the coming months.
Estimated to be around 180 feet across, 2024 YR4 is considered one of the most dangerous known asteroids in our solar system. However, its current size estimate may be inaccurate due to limitations in ground-based telescopes, which can only see reflected sunlight from the asteroid’s surface.
The JWST will study the heat emitted by the asteroid itself using its infrared instruments, providing a more accurate size and surface composition assessment. This data will help scientists better understand the hazard represented by an 180-foot-wide asteroid compared to one of 40 or 90 meters in size.
JWST will observe 2024 YR4 twice over the next few months, with initial observations planned for March as the asteroid reaches its peak brightness. The telescope’s observations come from JWST’s “director’s discretionary time,” allowing for a limited but critical viewing opportunity before the asteroid’s next close approach in 2028.
The data collected from these observations will be made publicly available, providing valuable insights into one of our solar system’s most pressing concerns: asteroid detection and mitigation.
Source: https://www.livescience.com/space/asteroids/in-emergency-decision-james-webb-telescope-will-study-city-killer-asteroid-2024-yr4-before-its-close-approach-to-earth