Posted by Davin Flateau on 7 Sep 2005 at 4:00 pm.
Filed under Astronomy.
In a huge celestial feast, a fast spinning pulsar is in the process of gobbling up its poor stellar companion. The European Space Agency’s Integral space observatory, together with NASA’s Rossi X-ray Timing Explorer spacecraft, has found a fast-spinning pulsar in the process of devouring its companion.
The observations support a theory that fast spinning pulsars get their high spin rate from such cannibalism. As material falls from the companion star into the pulsar, the energy is converted to increased spin in much the same way an ice skater increases spin by pulling in arms to the body. When spinning material moves closer to the axis of rotation, the rotation speed increases through a fundamental law of physics called the conservation of angular momentum.
‘Pulsars’ are rotating neutron stars, which are created in stellar explosions. They are the remnants of stars that were once at least eight times more massive than the Sun.
Neutron stars are born rapidly spinning in collapses of massive stars. They gradually slow down after a few hundred thousand years. Neutron stars in binary star systems, however, can reverse this trend and speed up with the help from the companion star. For the first time ever, this speeding-up has been observed in the act. “We now have direct evidence for the star spinning faster whilst cannibalising its companion, something which no one had ever seen before for such a system,” said Dr Lucien Kuiper from the Netherlands Institute for Space Research (SRON), in Utrecht.
You can read more at the ESA web site.
