Characterization of Stellar Spots in Next-Generation Microlensing Surveys

TL;DR

This paper studies how stellar spots affect microlensing light curves and assesses the potential to extract spot characteristics from future high-cadence surveys, highlighting the feasibility of constraining spot size and location.

Contribution

It provides a detailed analysis of spot-induced perturbations in microlensing events and evaluates the parameter retrieval accuracy in upcoming surveys.

Findings

Spot size and location can be well constrained from light curves.

Shape and surface brightness contrast are difficult to precisely determine.

High-cadence surveys improve parameter estimation accuracy.

Abstract

One of the important microlensing applications to stellar atmospheres is the study of spots on stellar surface provided by the high resolution of caustic-crossing binary-lens events. In this paper, we investigate the characteristics of spot-induced perturbations in microlensing light curves and explain the physical background of the characteristics. We explore the variation of the spot-induced perturbations depending on various parameters characterizing the spot and investigate how well these parameters can be retrieved from observations in high-cadence future lensing surveys. From this, we find that although it would not be easy to precisely constrain the shape and the surface brightness contrast, the size and location of the spot on the stellar surface can be fairly well constrained from the analysis of lensing light curves.