55
€Sometimes both techniques can be used on the same star
€And often two separate field strengths can be determined
Þ field strengths at the two poles are different;
Þ decentred dipole, or more complex field
(superposition
of multipoles)
Þ field strengths at the two poles are different;
Þ decentred dipole, or more complex field
(superposition
of multipoles)€Generally accretion takes place preferentially near lower-field pole
Polars:
measuring the magnetic field
MR
Ser
Schwope et al (1993)