Powerful explosions suggest neutron star missing link

This artist rendering depicts how a magnetar might appear if we could travel to one and view it up close, something that would not be advisable. Click here for more information.

GREENBELT, Md. - Observations from NASA's Rossi X-ray Timing Explorer (RXTE) have revealed that the youngest known pulsing neutron star has thrown a temper tantrum. The collapsed star occasionally unleashes powerful bursts of X-rays, which are forcing astronomers to rethink the life cycle of neutron stars.

"We are watching one type of neutron star literally change into another right before our very eyes. This is a long-sought missing link between different types of pulsars," says Fotis Gavriil of NASA's Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore. Gavriil is lead author of a paper in the February 21 issue of Sciencexpress.

A neutron star forms when a massive star explodes as a supernova, leaving behind an ultradense core. Most known neutron stars emit regular pulsations that are powered by rapid spins. Astronomers have found nearly 1,800 of these so-called pulsars in our galaxy. Pulsars have incredibly strong magnetic fields by Earthly standards, but a dozen of them - slow rotators known as magnetars - actually derive their energy from incredibly powerful magnetic fields, the strongest known in the universe. These fields can stress the neutron star's solid crust past the breaking point, triggering starquakes that snap magnetic-field lines, producing violent and sporadic X-ray bursts.

But what is the evolutionary relationship between pulsars and magnetars" Astronomers would like to know if magnetars represent a rare class of pulsars, or if some or all pulsars go through a magnetar phase during their life cycles.