Polarimetry and the Envelopes of Magellanic B[e] Supergiants

TL;DR

This paper investigates the circumstellar envelopes of Magellanic B[e] supergiants using spectroscopy and polarimetry, revealing their non-spherical, variable nature and demonstrating spectropolarimetry's effectiveness in studying their structure.

Contribution

It provides the first detailed polarization changes across spectral features and highlights the envelopes' non-axisymmetric ejections, advancing understanding of B[e]SG envelope morphology.

Findings

Envelopes are non-spherical and variable.

Spectropolarimetry reveals detailed polarization changes.

Large non-axisymmetric ejections occur.

Abstract

We discuss the nature of the circumstellar envelopes around the B[e] supergiants (B[e]SG) in the Magellanic Clouds (MC). Contrary to those in the Galaxy, the MC B[e]SG have a well defined luminosity and can be considered members of a well defined class. We discuss spectroscopy and optical broadband polarimetry and spectropolarimetry data. These data show for the first time detailed changes in the polarization across several spectral features. We show that the envelopes of the B[e]SG are generally variable. Broadband polarimetry data show that the envelopes are definitely non-spherically symmetric and large non-axisymmetric ejections may occur. In addition to that, spectropolarimetry is coming of age as a tool to study the B[e]SG envelope structure.