The Hubble Space Telescope has observed a wandering magnetar, named SGR 0501+4516, moving through our galaxy. This discovery challenges previous assumptions about magnetar origins and may provide insights into fast radio bursts (FRBs).
Discovered in 2008 by NASA's Swift Observatory, SGR 0501+4516 is one of only about 30 known magnetars in the Milky Way. Magnetars are neutron stars, remnants of dead stars, with incredibly strong magnetic fields. SGR 0501+4516's magnetic field is a trillion times more powerful than Earth's.
Researchers initially believed SGR 0501+4516 formed in a supernova explosion, due to its proximity to the supernova remnant HB9. However, Hubble's decade-long study, combined with data from ESA's Gaia spacecraft, revealed that the magnetar's trajectory doesn't trace back to HB9 or any other known supernova remnant. This suggests it either formed in another way or is much older than its estimated 20,000 years.
Alternative Formation Theories
If SGR 0501+4516 wasn't born in a supernova, it may have formed through the merger of two lower-mass neutron stars or via accretion-induced collapse. Accretion-induced collapse occurs in binary star systems where a white dwarf pulls gas from its companion, growing too massive and collapsing into a neutron star.
Implications for Fast Radio Bursts
Magnetars formed through accretion-induced collapse could explain FRBs originating from older stellar populations, where recent supernovae are rare. SGR 0501+4516 is currently the best candidate in our galaxy for a magnetar formed through a merger or accretion-induced collapse, potentially linking magnetars to the enigmatic phenomenon of fast radio bursts.