Feeds

Space watchers spot pulsar eating a star

Skeleton star gets gobbled

Build a business case: developing custom apps

Astronomers using NASA's Swift and Rossi X-Ray Timing Explorer (RXTE) satellites have discovered a stellar skeleton, a remnant of a dying star that is being consumed by its pulsar companion. So little of the star's original material is left that it now barely masses more than Jupiter.

Artist depiction. A pulsar tears into a planet mass object. Credit: Aurore Simonnet, Sonoma State University

Artist depiction. A pulsar tears into a planet mass object.

Credit: Aurore Simonnet, Sonoma State University

The artist's impression shows material being torn from a tear drop shaped blob in the foreground, flowing in a stream into the pulsar in the upper right corner. The planet-sized collection of helium is all that remains of the star. As its outer layers are pulled away, the material builds into a disk around the pulsar. Eventually, this material produces an outburst that can be seen from Earth.

The light from such an outburst reached Earth this June, which is when astronomers became aware of the system, some 25,000 light years from our sun.

NASA says the SWIFT J1756.9-2508 system is one of the most bizarre objects ever discovered in space. The observations from the RXTE satellite suggest the pulsar, which contains roughly 1.4 solar masses, is about 10 miles in diameter, and is spinning 182.07 times per second.

"This means that the surface of the star is moving at about 7000 miles per second, or roughly four per cent the speed of light," said Deepto Chakrabarty, an associate professor of physics in MIT's Kavli Institute for Astrophysics and Space Research. "While we already know of several cases of pulsars that have consumed or vapourised most of the mass in their companion star, SWIFT J1756.9 is possibly the most extreme example."

The scientists describe the likely history of the system. It probably formed several billion years ago, and consisted of a seriously massive star and a smaller companion. The huge star would have burned itself out and gone supernova relatively quickly, leaving behind the pulsar.

As the smaller star aged, it began to swell up as its internal pressure grew. It enveloped the pulsar, draining orbital energy from the system and causing the two objects to draw slightly closer together. Now the pair are closer together than the Earth is to the Moon, and the smaller star orbits the pulsar once every 54 minutes or so.

The team at MIT says observations of the system provide "a rare opportunity for astronomers to examine how millisecond pulsars are spun up to such incredibly rapid speeds, and to determine their eventual fate". ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
Boffins attempt to prove the UNIVERSE IS JUST A HOLOGRAM
Is this the real life? Is this just fantasy?
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
China building SUPERSONIC SUBMARINE that travels in a BUBBLE
Shanghai to San Fran in two hours would be a trick, though
LOHAN tunes into ultra long range radio
And verily, Vultures shall speak status unto distant receivers
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
Galileo, Galileo! Galileo, Galileo! Galileo fit to go. Magnifico
I'm just a poor boy, nobody loves me. But at least I can find my way with ESA GPS by 2017
Astronomers scramble for obs on new comet
Amateur gets fifth confirmed discovery
prev story

Whitepapers

Top 10 endpoint backup mistakes
Avoid the ten endpoint backup mistakes to ensure that your critical corporate data is protected and end user productivity is improved.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Backing up distributed data
Eliminating the redundant use of bandwidth and storage capacity and application consolidation in the modern data center.
The essential guide to IT transformation
ServiceNow discusses three IT transformations that can help CIOs automate IT services to transform IT and the enterprise
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.