  Aims: This paper extends previous studies in modeling time varying linear
polarization due to axisymmetric magnetic fields in rotating stars. We use the
Hanle effect to predict variations in net line polarization, and use geometric
arguments to generalize these results to linear polarization due to other
mechanisms. Methods: Building on the work of Lopez Ariste et al., we use simple
analytic models of rotating stars that are symmetric except for an axisymmetric
magnetic field to predict the polarization lightcurve due to the Hanle effect.
We highlight the effects for the variable line polarization as a function of
viewing inclination and field axis obliquity. Finally, we use geometric
arguments to generalize our results to linear polarization from the weak
transverse Zeeman effect. Results: We derive analytic expressions to
demonstrate that the variable polarization lightcurve for an oblique magnetic
rotator is symmetric. This holds for any axisymmetric field distribution and
arbitrary viewing inclination to the rotation axis. Conclusions: For the
situation under consideration, the amplitude of the polarization variation is
set by the Hanle effect, but the shape of the variation in polarization with
phase depends largely on geometrical projection effects. Our work generalizes
the applicability of results described in Lopez Ariste et al., inasmuch as the
assumptions of a spherical star and an axisymmetric field are true, and
provides a strategy for separating the effects of perspective from the Hanle
effect itself for interpreting polarimetric lightcurves.
