Mysterious,massive,magnetic stars

A student called Matt Shultz has found a rare close binary composed of two massive stars with magnetic fields.

 The polarity of the star's surface magnetic field, north or south, is indicated by red and blue.

Yellow lines indicate the magnetic field lines running from the stellar surfaces.

The origin of magnetism amongst massive stars is something of a mystery, and this discovery may 

help to shed some light on the question of why any of these stars have magnetic fields,” said Shultz.

The first hypothesis is that the magnetic field is generated while the star is being formed; a second is that the magnetic field originates in dynamos driven by the violent mixing of material when two already-formed stars in a close binary merge.

The stars are close enough that their magnetospheres are likely to be interacting during the whole of their orbit around each other. This means that their magnetic fields may act as a giant brake, slowing down the stars.