A displacement as small as a few millimeters could create a typical gamma ray burst, Duncan said. On that day the star erupted with a flash more than 1,000 times as powerful as any yet observed. The gamma ray flash lasted almost six minutes. It exploded as much energy during the first second as the sun releases in 1,000 years. Scientists classify SGRs as magnetars, a 10-member family of neutron stars that has the peculiar characteristic of slowing in rotation very rapidly.
Theorists believe that a strong magnetic field is responsible for applying the breaks.
In May 1998, the rate was measured to be about 2 milliseconds per year. It then increased to about 4.5 milliseconds per year, and today is back to 2 milliseconds per year, Woods said. A rotation now takes almost one two-hundredth of a second longer to complete than it did last year. This is an important difference in a star that spins once every 5.16 seconds. Woods believes the August 27 burst caused the change.