Using photometry to probe the circumstellar environment of δ scorpII

Abstract

We acquired Johnson BV photometry of the binary Be disk system δ Scorpii during its 2009, 2010, 2011, and 2012 observing seasons and used it to probe the innermost regions of the disk. We found that several disk building events have occurred during this time, resulting in an overall brightening in the V band and reddening of the system. In addition to these long-term trends, we found cyclical variability in each observing season on timescales between 60 and 100 days. We were able to reproduce the changes in the magnitude and color of δ Sco using our theoretical models and found that variable mass-loss rates in the range 2.5-7.0 × 10-9 Myr-1 over 35 days can reproduce the observed increase in brightness. © 2013. The American Astronomical Society. All rights reserved..