Feeds

Space watchers spot pulsar eating a star

Skeleton star gets gobbled

Intelligent flash storage arrays

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". ®

Choosing a cloud hosting partner with confidence

More from The Register

next story
SECRET U.S. 'SPACE WARPLANE' set to return from SPY MISSION
Robot minishuttle X-37B returns after almost 2 years in orbit
LOHAN crash lands on CNN
Overflies Die Welt en route to lively US news vid
Experts brand LOHAN's squeaky-clean box
Phytosanitary treatment renders Vulture 2 crate fit for export
Carry On Cosmonaut: Willful Child is a poor taste Star Trek parody
Cringeworthy, crude and crass jokes abound in Steven Erikson’s sci-fi debut
Origins of SEXUAL INTERCOURSE fished out of SCOTTISH LAKE
Fossil find proves it first happened 385 million years ago
America's super-secret X-37B plane returns to Earth after nearly TWO YEARS aloft
674 days in space for US Air Force's mystery orbital vehicle
NASA eyeballs SOLAR HEAT BOMBS, MINI-TORNADOES and NANOFLARES on Sun
Astro boffins probe fiery star's hidden depths
Human spacecraft dodge COMET CHUNKS pelting off Mars
Odyssey orbiter yet to report, though - comet's trailing trash poses new threat
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Why cloud backup?
Combining the latest advancements in disk-based backup with secure, integrated, cloud technologies offer organizations fast and assured recovery of their critical enterprise data.
Win a year’s supply of chocolate
There is no techie angle to this competition so we're not going to pretend there is, but everyone loves chocolate so who cares.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.