Oddball Asteroid Outcasts Spied by Infrared Space Telescope

NASA's NEOWISE mission has tracked down an elusive family of asteroids that shun regular orbits in the asteroid belt, instead preferring a crazy roller coaster ride through the solar system's equatorial plane.

NASA's NEOWISE mission has tracked down an elusive family of asteroids that shun regular orbits in the asteroid belt, instead preferring a crazy roller coaster ride through the solar system's equatorial plane.

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These highly inclined asteroids are thought to be the product of a massive collision that fragmented a much larger asteroid, called Euphrosyne, some 700 million years ago. The impact, which is thought to be one of the last great impacts in the solar system's evolution, left the main 156 mile (260 kilometer) wide asteroid behind and a family of smaller chunks in this highly inclined orbital path.

Euphrosyne is one of the ten largest asteroids to exist in the asteroid belt between the orbits of Mars and Jupiter.

The Euphrosyne family of asteroids are of great interest to astronomers tracking near-Earth objects (NEOs) - through a delicate resonance with Saturn's gravity, Euphrosynes have, in the future, the potential to drop into orbits closer to Earth.

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"The Euphrosynes have a gentle resonance with the orbit of Saturn that slowly moves these objects, eventually turning some of them into NEOs," said Joseph Masiero, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. and lead scientist on the Euphrosynes study, in a JPL news release. "This particular gravitational resonance tends to push some of the larger fragments of the Euphrosyne family into near-Earth space."

Originally launched in 2009 to scan the whole infrared sky, the Wide-field Infrared Survey Explorer (or WISE) was retired in 2011 after running low on coolant. Now the WISE spacecraft has been re-booted to seek out NEOs in a mission called NEOWISE. It just so happens that the revived spacecraft is an ideal tool to find dark, high-inclination asteroids like the Euphrosynes.

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Masiero's team tracked and studied 1,400 Euphrosyne asteroids with NEOWISE, finding that they were large and dark with highly inclined and elliptical orbits.

With over 700,000 known objects in the asteroid belt, there are many more asteroids that have yet to be spotted. However, many are small and very dark, making surveys a very difficult task. NEOWISE, however, specializes in seeking out these hard to spot asteroids, identifying which ones occupy orbits that could, one day, encounter Earth. Characterizing the source of NEOs is therefore very important - a near-impossible task in the jumbled asteroid belt.

"Most near-Earth objects come from a number of sources in the inner region of the main belt, and they are quickly mixed around," said Masiero. "But with (the Euphrosyne family), in such a unique region, we are able to draw a likely path for some of the unusual, dark NEOs we find back to the collision in which they were born."

Source: NASA/JPL-Caltech

The asteroid Euphrosyne glides across a field of background stars in this time-lapse view from NASA's WISE spacecraft.

Dozens of videos of the Russian meteor were uploaded to Youtube soon after impact on the morning of Feb. 15, 2013, many of which originated from vehicle dashboard cameras (or "dash cams"). During the morning commute many drivers saw the bright orb grow and explode in the atmosphere. The resulting shock wave caused windows to blow out over a huge area injuring over 1,000 people -- mainly cuts and minor concussions.

The fireball light was as bright as a second sun for a brief moment before it broke up over the Urals region of Russia.

As seen in this CCTV footage, the meteor created its own shadows as it exploded during the morning commute.

The meteor contrail hung over the Urals city of Chelyabinsk, about 900 miles east of Moscow, for some time after impact.

A white contrail left by the meteor break-up over Chelyabinsk.

A building damaged by the meteor shock wave in the town of Kopeisk, Chelyabinsk Region. The windows were blown out by the powerful shock wave generated by the hypersonic meteor.

Damage to a pancake bar caused by the shock wave of a meteor in the town of Kopeisk, Chelyabinsk Region.

Damaged caused to the office of a local newspaper in the Urals city of Chelyabinsk by the shock wave of the meteor.

A shopper walks past a broken shop window caused by the meteor explosion over the Urals city of Chelyabinsk.

The meteor traveled faster than sound in the upper atmosphere, creating a powerful sonic boom that slammed into the populated Urals region -- the foce of the blast blew out windows and caused structural damage to some buildings.

Damage caused by the shock wave of a meteor that passed above the Urals city of Chelyabinsk on Feb. 15, 2013.

Bricks from a factory wall knocked down by the force of the meteor shock wave litter a street in the Urals city of Chelyabinsk.

A collection of small meteorite fragments found in the snow after the Feb. 15, 2013 airbust event.

A man holding meteorite fragments found near the Chebarkul Lake.

Detail of one of the suspected meteorite fragments recovered from Russia's Chelyabinsk region.

Replacing broken window panes destroyed by the shockwave from the meteor airburst, at Uralskaya Molniya ice rink.

Replacing broken window panes destroyed by the shockwave from the meteor airburst, at Uralskaya Molniya ice rink.

Replacing windows in the freezing Chelyabinsk region are a priority for the Russian authorities.

A woman replaces a window damaged by the shockwave of the meteorite fall in Chelyabinsk, Russia, Feb. 16, 2013.

Residents wait for a bus in a street in Chelyabinsk, Russia, Feb. 16, 2013, as life in Russia's Chelyabinsk Region returns to normal after Friday's meteor explosion.