Modeling Mid-Infrared Variability of Circumstellar Disks with
  Non-Axisymmetric Structure
  Recent mid-infrared observations of young stellar objects have found
significant variations possibly indicative of changes in the structure of the
circumstellar disk. Previous models of this variability have been restricted to
axisymmetric perturbations in the disk. We consider simple models of a
non-axisymmetric variation in the inner disk, such as a warp or a spiral wave.
We find that the precession of these non-axisymmetric structures produce
negligible flux variations but a change in the height of these structures can
lead to significant changes in the mid-infrared flux. Applying these models to
observations of the young stellar object LRLL 31 suggests that the observed
variability could be explained by a warped inner disk with variable scale
height. This suggests that some of the variability observed in young stellar
objects could be explained by non-axisymmetric disturbances in the inner disk
and this variability would be easily observable in future studies.
