Absolute parameters of AE For -- a highly active detached binary of late K type

TL;DR

This paper provides detailed photometric and spectroscopic measurements of the late K-type detached binary AE For, revealing oversized, active stars with significant magnetic activity and spot coverage, challenging existing stellar models.

Contribution

It offers precise absolute parameters for AE For's components and links their high activity to their oversized nature, contributing to understanding active low-mass stars.

Findings

Both stars are significantly oversized compared to models.

High activity levels cause emission lines and large light curve variations.

Stars are heavily spotted, affecting their observed properties.

Abstract

We present photometric and spectroscopic analysis of AE For -- a detached eclipsing binary composed of two late K dwarfs. The masses of the components are found to be 0.6314 +- 0.0035 and 0.6197 +- 0.0034 Msun and the radii to be 0.67 +- 0.03 and 0.63$ +- 0.03 Rsun for primary and secondary component, respectively. Both components are significantly oversized compared to theoretical models, which we attribute to their high activity. They show Halpha, Hbeta, Hgamma, Ca H and Ca K lines in emission, and are heavily spotted, causing large variations of the light curve.