NASA WISE Mission Discovers New Asteroid Families Between Mars and Jupiter

In the main belt between Mars and Jupiter, families of asteroids spin through space. Now, researchers have used NASA's Wide-field Infrared Survey Explorer (WISE) to make some new finds about these objects. They've made a new and improved family tree for these asteroids.

The main asteroid belt is a major source of near-Earth objects (NEOs), which are asteroids and comets that come within 28 million miles of Earth's path around the sun. While most of these objects miss our planet, a few of them have the potential to impact the surface of Earth. Some of these near-Earth objects start out in stable orbits in the main asteroid belt until a collision or gravitational disturbance causes them to go hurtling off into space. With the potential for so much damage, understanding this asteroid belt is crucial.

In order to actually examine the belt, astronomers used millions of infrared snapshots from the asteroid-hunting portion of the WISE all-sky survey, called NEOWISE. In all, the researchers looked at about 120,000 main belt asteroids out of the approximately 600,000 known. They found that about 38,000 of these objects could be assigned to 76 families--28 of which are new. In fact, some asteroids thought to belong to one family were reclassified into a new one.

What is an asteroid family? An asteroid family is born when a collision breaks apart a large parent body into fragments of various sizes. Some collisions leave giant clusters while others result in numerous fragments. These pieces move together in packs before eventually splitting up over time. Since these pieces are made from the same mineral types, though, researchers can calculate which asteroids belong to which families.

"We're separating zebras from the gazelles," said Joseph Masiero of NASA's Jet Propulsion Laboratory in a news release. "Before, family members were harder to tell apart because they were travelling in nearby packs. But now we have a better idea of which asteroid belongs to which family."

The findings have enormous implications for reconstructing asteroids and understanding their origins. In addition, it could reveal a little bit more about the behavior of these objects which could, in turn, allow scientists to better predict their trajectories.