chandra_vela_writethrough_000607 ROCHESTER, N.Y. -- The energetic ember of an annihilated star is producing bright X-ray features that look like the poised bows of two eager archers. A new image from the Chandra X-ray Observatory shows the effects of a spinning pulsar as it fires out super-strong jets of material while shooting through space. Chandra associates are calling the picture one of the telescope's "most bizarre images yet."
The observation comes from an area in the constellation Vela where a star destroyed itself in a tremendous supernova explosion that would have been visible from Earth more than 10,000 years ago. Most of the star is now scattered across a large region of space. What remains at the core of the former parent star is a spinning neutron star called a pulsar.
What is a neutron star?
A neutron star is what remains after a supernova explosion when the core of material at the center of a star collapses into a dense mass of neutrons. Neutron stars generally have the mass of the sun packed into an area about 12 miles (19 kilometers) in diameter. They spin rapidly in cycles that range from milliseconds to a few seconds.
Vela rotates about 10 times per second. What distinguishes it from other neutron stars and designates it a pulsar is the fact it appears from Earth to flash with a bright pulse of radiation that matches the period of its rotation.
"They are very efficient accelerators of elementary particles, similar to our accelerators in nuclear laboratories."
The high density and rapid rotation turns the neutron star into a mighty power generator. It becomes highly magnetized and is able to produce jets and streams of material that shoot out from its poles at velocities near the speed of light.
"They are very efficient accelerators of elementary particles, similar to our accelerators in nuclear laboratories," said Pennsylvania State University astronomer George Pavlov, who announced the Chandra observation.
The image shows a bow-like structure at the leading edge of the cloud, or nebula, embedded in the Vela supernova remnant.
"What is particularly interesting about this pulsar is that the direction of the jets is exactly co-aligned with the direction of the pulsar's motion," Pavlov said. The forward-pointing jet shoots ahead, then appears to be deflected and showers backward as if deflected by the interstellar material it hits. The rear-pointing jet, which is the brighter of the two, shoots straight out.
"The brighter jet looks like a rocket exhaust," Pavlov said. "It is very tempting to assume that we have something like a rocket that this jet is generating."
Calculations show that this is not what is driving the pulsar's current motion. Pavlov said some sort of rocket-like propulsion may have been created when the pulsar was first formed, if a jet at one of the pulsar's poles were much stronger and faster than that at the other.
The Vela pulsar in the new Chandra image is especially intriguing because it appears to be moving fast through the expanding cloud of stellar debris.
Rocket-like propulsion may have been created if a jet at one of the pulsar's poles were much stronger and faster than that at the other, Pavlov explained.
The strange structure produced by the complicated dynamics of the Vela pulsar are encouraging to scientists because they are reminiscent of the wild structure Chandra detected in the Crab Nebula last fall.
Astronomers say the Vela observation is important because it shows that the Crab system, in which the central pulsar seems to be moving at high velocities with respect to the rest of the supernova remnant, is not unique.
"It seems that this is probably a very common property of these objects," Pavlov said.
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