by Mike Wall, SPACE.com Senior Writer
Date: 03 November 2011 Time: 02:01 PM ET
Astronomers have found the brightest and youngest example yet of a fast-spinning star, suggesting that the extremely luminous versions of these super-dense objects may be far more common than thought...
..The pulsar's extreme brightness and youth challenge current ideas about how super-bright millisecond pulsars form and how widespread they may be, researchers said...
...When a mass as great as our sun's is packed into a space the size of a city, the conserved angular momentum causes the resulting neutron star to spin very rapidly and to emit a ray of high-energy light that sweeps around like a lighthouse beam.
This light appears to pulse because astronomers see the beam only when it's pointed at Earth. "Normal" pulsars rotate at a rate between 7 and 3,750 revolutions per minute, but millisecond pulsars can spin much faster — up to 43,000 rotations per minute...
J1823-3021A also appears to have a much stronger magnetic field than other millisecond pulsars. The exotic object's combination of characteristics is likely to have astronomers scratching their heads, Freire said.
..."It challenges the way we believe millisecond pulsars form," he said. "It was not thought that, for the spin period of this object (5.44 ms), they could be so energetic and have such a high magnetic field."...
...The researchers aren't yet sure whether millisecond pulsar formation theories will need a tweak or a serious overhaul.
"We are currently investigating a number of possibilities," study co-author Michael Kramer, director of the Max Planck Institute for Radio Astronomy, said in a statement. "Nature might even be forming millisecond pulsars in a way we have not anticipated."
http://www.space.com/13488-brightest-spinning-pulsars-nasa-fermi-telescope.html
No comments:
Post a Comment