They cannibalize nearby objects

May 22, 2009 17:41 GMT  ·  By
An impression of how an ageing pulsar (right) sucks up matter from a companion star
   An impression of how an ageing pulsar (right) sucks up matter from a companion star

Millisecond pulsars are the fastest spinning objects in the Universe, rotating around themselves up to tens of times per second. They are the remnants of supernova explosions, created by giant stars at the end of their burning cycle. But astronomers have found no intermediary stages in the life of a pulsar until now, apart from very young and very old ones. Such a discovery, which was stumbled upon only recently, shows that old pulsars are able to cannibalize on their stellar neighbors, in order to revive themselves. The find has the potential to change the way experts look at this class of formations.

“It’s really a missing link in the chain from young pulsar to old pulsar,” McGill University graduate student Anne Archibald, who is also the lead author of a new scientific study detailing the find, published in the Thursday issue of the respected journal Science, explained. Regularly, pulsars are born from the wreaks of supernovas already spinning super-fast, but, over time, their rotational period decreases, until they are no longer able to spread energy around them and come to a stand-still. This is commonly known as a star's second death.

However, in previous studies, experts observed that pulsars they once considered to be dead or inactive suddenly became millisecond pulsars, as in they began to shed matter and energy once more. The newly discovered object, which was captured on photo at various time frames, appears to be the missing link that explains this peculiar phenomenon. The new theory has it that all pulsars have a companion star around them, from which they occasionally take up extra matter, to fed on. This matter concentrates around the pulsar, creating what is known as an accretion disc. When enough matter is collected, it falls into the star, and imparts angular momentum, allowing it to start spinning again.

The process is very similar to recycling, experts maintain. In fact, they name this particular class of revived stellar formations “recycled pulsars.” “We mean it in the same sense as recycling your plastics. These pulsars have died and become invisible and useless to us, but they get brought back to life by getting fed from a companion,” Archibald added. “This is a completely new thing, seeing it go from one state to another. We’ve never seen that before, ever,” West Virginia University expert Maura McLaughlin, the co-author of the Science paper, shared.

The recently identified celestial object was discovered by the Green Bank Telescope in West Virginia, and was located some 4,000 light-years away. Spinning 592 times per second, the object is one of the fastest ever recorded. It was classified as J1023, Wired reports.

“Studying this system will teach us an awful lot about the recycling process. We may see the radio pulsations disappear and come back again a year from now. There are lots of neat things we can do,” McLaughlin told. “It’s a bit of a landmark in tying together what we think happens in these dead stars. You can see the transitions and understand more about how both of these stars work. That’s a great deal of fun,” University of California in Berkeley (UCB) Astronomer Don Backer, who has been one of the first space observers to discover a millisecond pulsar, concluded.