This illustration represents the recently discovered magnetar SGR 0418+5729.
Magnetars are pulsars (spinning neutron stars) characterized by long rotations periods, occasional episodes of extremely enhanced emission (about 10–100 times the usual value) and intense, short bursts of X-rays and gamma-rays; these highly energetic events are presumed to be powered by an intense magnetic field.
Unlike all other magnetars detected so far, SGR 0418+5729 has a relatively weak dipolar magnetic field, B<7.5 x 1012 Gauss, which is 2–3 orders of magnitude lower than the typical value for a magnetar. Astronomers deduce that the magnetar-like activity of SGR 0418+5729 is powered by a strong, internal magnetic field, B~5 x 1014 Gauss, which is undetectable by observations.
The curves converging at the poles of the magnetar represent the dipolar magnetic field lines, whereas the entangled lines inside the magnetar symbolize the internal magnetic field.
Illustration credit: European Space Agency
Notes: For more information, see Are Most Pulsars Really Magnetars in Disguise? The initials "SGR" stand for "Soft Gamma Repeater."
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