Infrared excess in the Be star δ Scorpii

We present infrared photometric observations of the Be binary system δ Scorpii obtained in 2006. The J, H, and K magnitudes are the same within the errors compared to observations taken 10 months earlier. We derive the infrared excess from the observation and compare this to the color excess predicted by a radiative equilibrium model of the primary star and its circumstellar disk. We use a non-LTE computational code to model the gaseous envelope concentrated in the star's equatorial plane and calculate the expected spectral energy distribution and Hα emission profile of the star with its circumstellar disk. Using the observed infrared excess of δ Sco, as well as Hα spectroscopy bracketing the IR observations in time, we place constraints on the radial density distribution in the circumstellar disk. Because the disk exhibits variability in its density distribution, this work will be helpful in understanding its dynamics.