The Large Scale Behaviour in the Disk of $\delta$ Scorpii from 2000-2018.

We model the circumstellar disk of $\delta$ Sco using the 3-dimensional Monte Carlo radiative transfer code HDUST in order to quantify the large scale changes in the disk through the years 2000 to 2018, and to see if these changes can be attributed to the secondary star affecting the disk throughout its orbit. We determine our best-fitting models through matching simulated observations to actual H$\rm \alpha$ spectroscopy and V-band photometric observations. Our modelling results confirm previous findings that the disk of $\delta$ Sco was forming early in the century. We also find a period of disk dissipation when the companion is at apastron, as well as a significant growth of the disk between 2009 and 2011, prior to the periastron of 2011. Due to the steady-state nature of the disk after 2011, it is difficult to say whether the variations seen are due to the effect of the close passage of the binary companion.