When a massive star explodes as a supernova, a neutron star is formed. Pulsars are neutron stars with incredibly strong magnetic fields. These stars spin rapidly, emitting pulsations. To date, astronomers have found nearly 1,800 of these so-called pulsars in our galaxy.
Magnetars are slow rotators that derive their energy from the strongest magnetic fields known in the universe. Those fields are so powerful that they produce violent and sporadic X-ray bursts after causing immense stress to the neutron star’s solid crustso that “starquakes” are triggered. According to Robert Naeye from the Goddard Space Flight Center, it is unclear whether magnetars represent a rare class of pulsars, or if some or all pulsars go through a magnetar phase during their life cycles.
PSR J1846, the pulsing neutron star, is considered to be no older than 884 years old, making it a very young star. Magnetars, on the other hand, are assumed to be about 10,000 years old. Observations from NASA’s Chandra X-ray Observatory showed that following PSR J1846’s X-ray bursts that occurred in 2006, the star’s spectrum changed to a more magnetar-like spectrum.
“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.
This star’s magnetic field is considered to be incredibly strong compared to Earth’s field, and yet much weaker than typical magnetar field strengths. “PSR J1846’s actual magnetic field could be much stronger than the measured amount, suggesting that many young neutron stars classified as pulsars might actually be magnetars in disguise, and that the true strength of their magnetic field only reveals itself over thousands of years as they ramp up in activity,” explains Victoria Kaspi of McGill University.
TFOT recently reported on a comet named Holmes that brightened unexpectedly in mid-October 2007, as it rushed through our solar system. The comet became extremely bright and was visible to the naked eye. Other astronomical findings recently covered by TFOT include the discovery of three new planets orbiting a sun almost 1,000 light years away from Earth,the first conclusive evidence for water on an extra solar planet located some 63 light years away from Earth, and the first ever quadruple-star system, which may also contain planets.
More information about this new discovery regarding PSR J1846 can be found on NASA’s website.
Image: An 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 (Credit: Sky & Telescope, Gregg Dinderman).