Monitoring the Polarimetric Variability of \delta\ Scorpii

TL;DR

This study presents long-term polarimetric monitoring of the Be star eltaScorpii, revealing variable polarization correlated with brightness changes and disk disturbances during periastron passages.

Contribution

It provides the first extensive polarimetric dataset of eltaScorpii over several years, linking polarization variability to disk density changes and periastron events.

Findings

Disk density varied since 2006

Polarization correlates with photometric light curve

Disk disturbance observed during 2011 periastron

Abstract

The Be star \delta\ Scorpii is an interesting binary system, whose primary companion created a circumstellar disk after the periastron passage of the secondary in 2000, being since then classified as Be. This work presents the results of a long-term monitoring of this star in broad-band imaging polarimetry. The observational data collected since 2006 in the Pico dos Dias Observatory (Brazil) show a variable polarization that seems to correlate with the photometric light curve. From this data we see that the disk density varied since 2006; furthermore, the data suggests that there was some disturbance of the disk during the last periastron passage in July, 2011.