respectively. Yellow lines Indicates the magnetic field lines running from stellar surfaces.
Credit: Volkmar Holzwarth, KIS, Freiburg.
The first massive star, epsilon Lupi, in which both stars
have magnetic fields, has been discovered by a PhD student, Matt Shultz.
A binary Star is a star system consisting of two of more
stars, orbiting around their center of mass.
For the past few years, the BinaMiCS collaboration, formed
to study the magnetic properties of close binaries, has been trying to find
such an object. They have now found one using Canada-France-Hawaii Telescope.
Mr. Shultz said that the origin of magnetism amongst the
massive stars is something of a mystery. And the discovery may help to shed
some light on the question why these stars have magnetic fields.
In stars, such as the sun, Magnetic fields are generated by
convection in the outer portion of the star. However, there is no convection in
the outer surface of the massive star, so there is no support of the magnetic
dynamo. Nevertheless approximately 10 percent of massive stars have strong
magnetic fields.
Two explanations have been brought forward to explain this,
The first hypothesis is that the magnetic field is generated
while the star is being formed; the second is that the magnetic field
originated in dynamos driven by the violent mixing of stellar plasma when two
stars in a close binary merge.
The researcher shows the strengths of the magnetic fields
are similar in the two stars; however their magnetic axes are anti-aligned,
with the south pole of one star pointing in approximately the same direction as
the North Pole of the other.
“We’re not sure why that is yet, but it probably points to
something significant about how the stars are interacting with one another.
We’ll need to collect more data.”
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