Neutron Star Seen Forming Exotic New Matter

The dense core of a nearby collapsed star is undergoing a rapid chill, providing the first direct evidence that such stars can produce a superfluid of neutrons – a state of matter that cannot be created in laboratories on Earth. Neutron stars are the remnants of exploded stars. Their cores are so dense that atomic nuclei dissolve, and protons and electrons combine to form a soup dominated by neutrons. If conditions are right, these neutrons ought to be able to pair up to form a superfluid – a substance with quantum properties that mean it flows with zero friction.

It has long been assumed that neutrons in the cores of neutron stars become superfluid, but without any direct evidence that they do so. That changed in 2010, when astrophysicists examined measurements taken by NASA's orbiting Chandra X-ray Observatory of the 330-year-old neutron star at the heart of the dusty supernova remnant Cassiopeia A. These measurements show the star has dimmed by 20 per cent since it was discovered in 1999, corresponding to an estimated temperature drop of 4 per cent. Now colleagues have calculated that this rapid cooling can be explained if a fraction of the neutrons in the core are undergoing a transition to superfluidity.

Neutron Star Packs Two Suns' Mass in Size of City

Astronomers have discovered what they say is the mightiest neutron star yet. The super-dense object, which lies some 3,000 light-years from Earth, is about twice as massive as our Sun. That is 20% greater than the previous record holder, the US-Dutch team behind the observation tells the journal Nature. "It's approximately the size of a city, which for an astronomical object is interesting because people can conceive of it pretty easily," the study's lead author told BBC News.

The finding is important, says Dr Demorest's team, because it puts constraints on the type of exotic material that can form a neutron star. Such objects are thought to be the remnant cores of once giant stars that blew themselves apart at the ends of their lives. As well being fantastically compact, the cores also spin incredibly fast. This particular object, classified as PSR J1614-2230, revolves 317 times a second. It is what is termed a pulsar - so-called because it sends out lighthouse-like beams of radio waves that are seen as radio "pulses" every time they sweep over the Earth.

Chandra Finds Evidence for Stellar Cannibalism

Evidence that a star has recently engulfed a companion star or a giant planet has been found using NASA's Chandra X-ray Observatory. The likely existence of such a "cannibal" star provides new insight into how stars and the planets around them may interact as they age.

The star in question, known as BP Piscium (BP Psc), appears to be a more evolved version of our Sun, but with a dusty and gaseous disk surrounding it. A pair of jets several light years long blasting out of the system in opposite directions has also been seen in optical data. Astronomers have suggested that BP Psc is an old star in its so-called red giant phase. And, rather than being hallmarks of its youth, the disk and jets are, in fact, remnants of a recent and catastrophic interaction whereby a nearby star or giant planet was consumed by BP Psc.

Magnetic Mega-star Challenges Black Hole Theory

A neutron star with a mighty magnetic field has thrown down the gauntlet to theories about stellar evolution and the birth of black holes, astronomers reported on Wednesday. The "magnetar" lies in a cluster of stars known as Westerlund 1, located 16,000 light years away in the constellation of Ara, the Altar.

Within Westerlund 1 is the remains of one of galaxy's few magnetars -- a particular kind of neutron star, formed from the explosion of a supernova, that can exert a magnetic field a million, billion times strong than Earth's.