Dead star found to be hiding strongest magnet in the universe
Monday, August 19, 2013, 5:26 -
Scientists at the European Space Agency have made a curious discovery about a dead neutron star.
Once thought to have an unusually low magnetic field, it appears to be hiding one of the strongest magnets in the universe -- trillions of times greater than those found on Earth.
The star, called SGR 0418+5729 -- or SGR 0418 for short -- is 6,500 light years from Earth.
Its mass is greater than our Sun, but it is incredibly small, measuring only 20 km across.
Scientists are calling the star a magnetar -- a neutron star with an extremely powerful magnetic field.
SGR 0418 was detected in June 2009, and scientists have been studying it ever since.
"Until very recently, all indications were that this magnetar had one of the weakest surface magnetic fields known; at 6 x 1012 Gauss, it was roughly a 100 times lower than for typical magnetars,” said Andrea Tiengo, lead author of the paper, in a statement.
"Understanding these results was a challenge. However, we suspected that SGR 0418 was in fact hiding a much stronger magnetic field, out of reach of our usual analytical techniques."
Normally, scientists determine the magnetic field of a magnetar by measuring the rate at which the star's spin is declining, but for SGR 0148, researchers searched for variations in the X-ray spectrum of the magnetar over short time intervals.
"This method allows astronomers to analyse the magnetic field in much more detail and has revealed SGR 0418 as a true magnetic monster," ESA writes.
The full paper has been published in Nature magazine.