BBC Focus Magazine

[Shadowwolf]

Pulsars are among the most exotic celestial bodies known. They have diameters of about 20 kilometres, but at the same time roughly the mass of our sun. A sugar-cube sized piece of its ultra-compact matter on Earth would weigh hundreds of millions of tons. A sub-class of them, known as millisecond pulsars, spin up to several hundred times per second around their own axes. Previous studies reached the paradoxical conclusion that some millisecond pulsars are older than the universe itself.

Astrophysicist Thomas Tauris from the Max Planck Institute for Radio Astronomy and the Argelander Institute for Astronomy in Bonn could resolve this paradox by computer simulations. Through numerical calculations on the base of stellar evolution and accretion torques, he demonstrated that millisecond pulsars loose about half of their rotational energy during the final stages of the mass-transfer process before the pulsar turns on its radio beam. This result is in agreement with current observations and the findings also explain why radio millisecond pulsars appear to be much older than the white dwarf remnants of their companion stars -- and perhaps why no sub-millisecond radio pulsars exist at all. The results are reported in the February 03 issue of the journal "Science."

http://www.sciencedaily.com/releases/2012/02/120202151436.htm