An odd asteroid's peculiar tail is far longer than previously thought, stretching nearly three times the distance from Earth to the moon, scientists say.
The surprising tail of dust streaming from the asteroid P/2010
A2is about 620,000 miles (1 million kilometers) long, new photos
taken by the One Degree Imager (ODI) camera at the WIYN telescope in Arizona reveal.
"Previous images of A2 clearly indicated the tail
extended beyond those relatively small fields of view; we wanted to use the
superb image quality over a wide field that ODI offers to see just how
much," Jayadev Rajagopal, WIYN scientist at the National Optical Astronomy Observatory in Tucson, Ariz., said in a statement. "But
I don't think we were quite expecting to see a tail that extends out to and
beyond even the ODI field!"
It's rare to see an asteroid with a tail, and
astronomers initially thought P/2010 A2 was a comet upon its discovery in 2010.
But the picture became clearer after NASA's iconic Hubble Space
Telescope photographed the object a month or so after it was
first spotted circling the sun in the main asteroid belt between Mars and
Jupiter.
The Hubble observations led astronomers to estimate
that anasteroid 10
to 16 feet (3 to 5 meters) wide may have slammed into P/2010 A2's core, which
is about 390 feet (120 meters) wide.
This cosmic smashup was likely as powerful as an
atomic bomb, vaporizing the smaller space rock and stripping material from
P/2010 A2. Sunlight and the stream of charged particles from the sun known as
the solar wind then swept these dusty bits into a tail, the theory goes.
Over time, the centimeter-size particles in P/2010
A2's tail will form a meteor stream around the sun, as happens with debris shed
by comets, scientists said.
Asteroid collisions and other debris-spewing events
add to a cloud of dust spread around our solar system. The new images from the
ODI camera will shed light on how much material asteroids contribute to this
"zodiacal dust," researchers said.
Follow Mike Wall on Twitter @michaeldwall and Google+. Follow
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published on SPACE.com.
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