Polarization profiles for selected microlensing events towards the galactic bulge

TL;DR

This paper explores how gravitational microlensing can enhance polarization signals from different types of stars, providing a new method to study stellar atmospheres through polarization profiles during high magnification events.

Contribution

It demonstrates the potential of microlensing-induced polarization profiles to analyze stellar atmospheres for various star types, highlighting the polarization strength variations.

Findings

Polarization can reach about 0.04% for late type stars.

Polarization can be up to a few percent for cool giants.

Highly magnified microlensing events significantly enhance polarization signals.

Abstract

Gravitational microlensing, in case of relevant finite source size effects, provides an unique tool for the study of stellar atmospheres through the enhancement of a characteristic polarization signal. Here, we consider a set of highly magnified events and show that for different types of source stars (as hot, late type main sequence and cool giants) showing that the polarization strength may be of $\simeq 0.04$ percent for late type stars and up to a few percent for cool giants.