Modeling Mid-Infrared Variability of Circumstellar Disks with Non-Axisymmetric Structure

TL;DR

This paper explores how non-axisymmetric structures like warps or spiral waves in the inner disks of young stellar objects can cause mid-infrared variability, emphasizing the importance of vertical structure changes over simple perturbations.

Contribution

It introduces models of non-axisymmetric inner disk variations, such as warps and spiral waves, to explain mid-infrared variability in young stellar objects, extending beyond previous axisymmetric models.

Findings

Precession of non-axisymmetric structures causes negligible flux variation.

Changes in the height of these structures lead to significant flux variations.

Application to LRLL 31 suggests a warped disk explains observed variability.

Abstract

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.