Object Analysis

SGR 1806-20 is a magnetar—a type of neutron star with an incredibly powerful magnetic field—located about 50,000 light-years away in the constellation Sagittarius. It is one of the most extreme objects in the galaxy, with a magnetic field quadrillions of times stronger than Earth's.

In December 2004, SGR 1806-20 released a "giant flare" of gamma rays that was the brightest event ever recorded in the galaxy from Earth. For a fraction of a second, the star released more energy than the Sun emits in 150,000 years. Even from 50,000 light-years away, the flare significantly affected Earth's upper atmosphere and blinded many satellite sensors.

These flares are caused by "starquakes"—violent ruptures in the neutron star's solid crust caused by the intense stress of the magnetic field. SGR 1806-20 is located within a massive star-forming region and is likely the remnant of a star that was once at least 40 times more massive than the Sun.