magnetic massive star
setâre-ye porjerm-e meqnâtisi
Fr.: étoile massive magnétique
A → stellar magnetic field associated with
a → massive star.
Magnetic fields are detected only for seven to ten percent of all
studied massive → OB stars, and the
magnetic field occurrence does not depend on the
→ spectral type. Because
these magnetic fields seem to be stable over long time-scales and their
strength does not seem to correlate with known stellar properties, it
is assumed that they are of fossil origin
(→ fossil magnetic field)
and are frozen into the → radiative envelope
of the stars.
The fields are those of the birth
→ molecular clouds, partly trapped inside
the → pre-main sequence star
during the cloud → collapse
phase, possibly further enhanced by a
→ dynamo effect in the early fully convective
Typically, the polar field strength ranges from about a
hundred → Gauss up to several kiloGauss.
However, some weaker fields,
below 100 G, have recently been detected.