Pan-STARRS discovers its first potentially hazardous asteroid

Scientists believe there are many more asteroids under a mile across that have not yet been discovered.Provided by the Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts
By | Published: September 28, 2010 | Last updated on May 18, 2023
Asteroid 2010 ST3
Two images of 2010 ST3 (circled in green) taken by PS1 about 15 minutes apart on the night of September 16 show the asteroid moving against the background field of stars and galaxies. Each image is about 100 arc seconds across.
September 28, 2010
The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) PS1 telescope has discovered an asteroid that will come within 4 million miles (6 million kilometers) of Earth in mid-October. The object is about 150 feet (45 meters) in diameter and was discovered in images acquired September 16, when it was about 20 million miles away (32 million km).

It is the first “potentially hazardous object” (PHO) to be discovered by the Pan-STARRS survey and has been given the designation “2010 ST3.”

“Although this particular object won’t hit Earth in the immediate future, its discovery shows that Pan-STARRS is now the most sensitive system dedicated to discovering potentially dangerous asteroids,” said Robert Jedicke from the University of Hawaii. “This object was discovered when it was too far away to be detected by other asteroid surveys.”

Scientists already have cataloged most of the largest PHOs, but they suspect there are many more under a mile across that have not yet been discovered. These could cause devastation on a regional scale if they ever hit our planet. Such impacts are estimated to occur once every few thousand years.

“I congratulate the Pan-STARRS project on this discovery,” said Timothy Spahr from the Minor Planet Center in Cambridge, Massachusetts. “It is proof that the PS1 telescope, with its Gigapixel Camera and its sophisticated computerized system for detecting moving objects, is capable of finding potentially dangerous objects that no one else has found.”

Pan-STARRS should discover tens of thousands of new asteroids every year with sufficient precision to accurately calculate their orbits around the Sun. Any sizable object that looks like it may come close to Earth within the next 50 years or so will be labeled “potentially hazardous” and carefully monitored. NASA experts believe that, given several years warning, it should be possible to organize a space mission to deflect any asteroid that is discovered to be on a collision course with Earth.

Pan-STARRS has broader goals as well. PS1 and its bigger brother, PS4, which will be operational later in this decade, are expected to discover a million or more asteroids in total, as well as more distant targets such as variable stars, supernovae, and mysterious bursts from galaxies across more than half the universe. PS1 became fully operational June 2010.