Astronomers  using the National Science Foundation’s Karl G. Jansky Very Large Array  (VLA) have discovered a fast-moving jet of material propelled outward  from a type of neutron star previously thought incapable of launching  such a jet. The discovery, the scientists said, requires them to  fundamentally revise their ideas about how such jets originate.

   Neutron stars are superdense objects, the remnants of massive stars  that exploded as supernovas. When in binary pairs with “normal” stars,  their powerful gravity can pull material away from their companions.  That material forms a disk, called an accretion disk, rotating around  the neutron star. Jets of material are propelled at nearly the speed of  light, perpendicular to the disk.

   “We’ve seen jets coming from all types of neutron stars that are  pulling material from their companions, with a single exception. Never  before have we seen a jet coming from a neutron star with a very strong  magnetic field,” said Jakob van den Eijnden of the University of  Amsterdam. “That led to a theory that strong magnetic fields prevent  jets from forming,” he added.

  The new discovery contradicts that theory.

   The scientists studied an object called Swift J0243.6+6124 (Sw J0243),  discovered on October 3, 2017, by NASA’s orbiting Neil Gehrels Swift  Observatory, when the object emitted a burst of X-rays. The object is a  slowly-spinning neutron star pulling material from a companion star that  is likely significantly more massive than the Sun. The VLA observations  began a week after the Swift discovery and continued until January  2018.