All celestial objects that are part of the Solar System appear to move against the background of stars; watching out for objects which change their position from hour to hour and day to day is the key to discovering Solar System objects. While the prime purpose of Pan-STARRS is finding those objects that are a danger to Earth, we expect to make major advances in many other areas of small-body research.
The primary aim of the Pan-STARRS project is to find potentially hazardous objects (PHOs). Pan-STARRS should find almost all of the objects 1-km diameter that pass close to the Earth and many of the 300-meter ones. For more information go our web page on Asteroid Threats, or the more detailed pdf report:
Beyond the NEOs, Pan-STARRS will contribute to studies of objects as near as our own solar system to the farthest reaches of the universe. Within the solar system, the majority of the moving objects that Pan-STARRS will discover will belong to the population of main-belt asteroids. Estimates for the number of such objects we will find and develop orbits for range up to the tens of millions, the smallest of which will be about 300 meters in diameter. While these asteroids themselves do not pose any threat to Earth, it is generally believed the NEOs that cross into the inner solar system originate in the main belt. Observations from Pan-STARRS will allow astronomers to characterize this population in terms of their size and orbital distributions. This will provide useful insights into the frequency of collisions and fragmentation of the main-belt asteroids, and the processes that "kick" objects from the main belt into orbits that eventually cross into the inner solar system.
Kuiper Belt Objects
Kuiper Belt objects (KBOs) are now known to comprise a large population in the outer solar system. Some of these objects are as large as 1000 km in diameter. These objects are found in a region that starts near the orbit of Neptune and extends into the outer solar system well beyond the orbit of Pluto. Pan-STARRS will allow planetary astronomers to discover many new KBOs and characterize their orbits. This will provide a firm understanding of the structure, dynamics, and evolution of the outer solar system. Pan-STARRS is also likely to be a productive tool for discovering comets, both active and inactive.
Other Solar System Science
Pan-STARRS will produce the deepest and most complete survey of the Solar System so far. We expect about 100,000 Jupiter Trojans asteroids, 1,000 Centaur asteroids, and several hundred comets.
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