Pulsar sends stellar disk fragment speeding into space

NASA's Chandra X-ray Observatory is keeping an eye on a runaway stellar disk that's picking up speed as it races off into outer space.

The space-based telescope first observed the escaped chunk of gas, several years ago, after witnessing a pulsar collide with its companion star's stellar disk, punching a hole in the ring of gas and dust. Now, astronomers say the disk fragment is picking up steam.

The binary star system is called PSR B1259-63/LS 2883, or B1259 for short. The pair consists of a pulsar, the dense stellar remnants of supernova explosion, and a larger star whose rotation rate is near break-up speed, spinning off material.

The pulsar's highly elliptical orbit sends it through the larger star's stellar disk every 41 months. On its most recent pass through, the pulsar -- whose ferocious spin rate sends out pulses of high-energy particles at near the speed of light -- punched a hole in the disk.

"These two objects are in an unusual cosmic arrangement and have given us a chance to witness something special," George Pavlov, an astronomer at Penn State University, said in a recent press release. "As the pulsar moved through the disk, it appears that it punched a clump of material out and flung it away into space."

Pavlov is the lead author of a new paper on the collision, published this week in the Astrophysical Journal.

Initial observations showed the disk fragment moving through space at 7 percent the speed of light. More recent observation show the gas and accelerated to 15 percent the speed of light -- likely propelled by the winds of the pulsar.

"This just shows how powerful the wind blasting off a pulsar can be," said co-author Jeremy Hare, an astronomer at George Washington University. "The pulsar's wind is so strong that it could ultimately eviscerate the entire disk around its companion star over time."