First images of Antares photosphere from spectropolarimetry

TL;DR

This paper presents the first direct images of Antares' photosphere using spectropolarimetry, revealing large convective cells and surface inhomogeneities similar to Betelgeuse, advancing understanding of red supergiant surfaces.

Contribution

It applies spectropolarimetric imaging techniques to Antares, demonstrating the presence of large convective cells and surface features, extending methods previously used for Betelgeuse.

Findings

Convective cells in Antares last several months.

Large convective cells occupy about 30% of the stellar radius.

Linear polarization signals are due to depolarization and brightness inhomogeneities.

Abstract

Antares is the closest red supergiant (RSG) to Earth. The discovery of linear polarization in the atomic lines of the star opens the path to produce direct images of the photosphere, hence probing the dynamics at the surface. We analyze this linear polarization signals following the same scheme as has been previously done for the RSG Betelgeuse, and find that they are comparable in all its details. This allows us to use the same models for the analysis of these polarization signals in both stars. We found that as in Betelgeuse, the linear polarization signal of Antares is due to the depolarization of the continuum combined with brightness inhomogeneities. This allows us to produce images of the photosphere of star. We show that in Antares, convective cells can last several months and occupy roughly 30\% of the stellar radius for the largest ones.