Dead stars known as magnetars — the most-magnetic objects in the universe — are a little less mysterious, thanks to new observations from the European Space Agency's XMM-Newton and Integral space telescopes.
Magnetars are are a type of star remnant called a neutron star. They have magnetic fields 10 million times larger than the strongest magnet ever created on Earth. Only 15 of these bizarre objects have ever been spotted.
A magnetar forms when an extremely massive star has exhausted its fuel for internal combustion, and collapses into itself. The gravity is so strong that all the matter in the star condenses into neutrons, and the resulting stuff is so dense that a teaspoon of it would weigh about a hundred million tons.
"Neutron stars are very interesting objects," said astrophysicist Maxim Lyutikov at Purdue University who worked on the new study. "They have the mass of a star, in a radius of only 10 kilometers [6.2 miles]. They are as dense as nuclear matter, and they rotate extremely fast."
On top of neutron stars' already wacky characteristics, magnetars add one more: a magnetic field a thousand times stronger than that of ordinary neutron stars. No one knows why some stars become magnetars, and some experts suggest they may even be the same as regular neutron stars, just seen at a unique phase of life.
The new observations, published in the* Astrophysical Journal*, confirmed the presence of a theorized cloud of electrons surrounding some magnetars. This cloud seems to be interacting with the light emitted from the stars, causing them to radiate a unique spectrum of X-rays, rather than the usual spread of light frequencies expected from normal stars. The electron clouds seen around the magnetars are much denser than any observed around other neutron stars, and they help explain the unique patterns of radiation they emit.
"It’s a very nice piece of the puzzle that fits in to the general scheme of how we think magnetars work," Lyutikov told Wired.com.
See Also:
- Scientists Find Rare, Ultramagnetic Star
- Pulsar's Explosion May Show Rare Stellar Evolution
- What's Prettier Than the Aftermath of a Star's Death?
Image: Sky & Telescope/Gregg Dinderman
**
