What potentially hazardous asteroid was identified on a close approach trajectory in January 2026?

The asteroid identified on a close approach trajectory in January 2026 as a potentially hazardous object was 2026 AZ1. This designation indicates that the asteroid met specific criteria established by astronomers to prioritize monitoring of space rocks that could pose a risk to Earth. A "Potentially Hazardous Asteroid" (PHA) is defined by two main parameters: its size and its minimum orbit intersection distance (MOID) with Earth. Specifically, an asteroid is considered a PHA if its MOID is 0.05 astronomical units (approximately 7.5 million kilometers or 19.5 lunar distances) or less, and its absolute magnitude (H) is 22.0 or less, which generally corresponds to an object larger than about 140 meters (460 feet) in diameter.

When astronomers identify an asteroid like 2026 AZ1 on a "close approach trajectory," it means its orbital path brings it relatively near Earth. These close approaches are routinely tracked by organizations such as NASA's Jet Propulsion Laboratory (JPL) Center for Near-Earth Object Studies (CNEOS). While the term "potentially hazardous" might sound alarming, it primarily serves as a classification to ensure these objects are closely observed and their orbits are precisely determined. The vast majority of identified potentially hazardous objects are not an impact threat for at least the next 100 years.

The discovery and subsequent classification of asteroids like 2026 AZ1 highlight the ongoing efforts in planetary defense. Scientists continuously monitor near-Earth objects to refine orbital data and assess any potential risks. This vigilance allows for early detection and detailed study of objects that could, in the distant future, pose a threat, ensuring that humanity has the knowledge and time to develop potential mitigation strategies if ever needed.