Doppler maps and surface differential rotation of EI Eri from the MUSICOS 1998 observations

TL;DR

This paper uses time-series Doppler imaging from multi-site observations to analyze surface features and differential rotation of the active binary star EI Eri, revealing weak solar-type differential rotation and poleward meridional flow.

Contribution

It provides the first detailed surface differential rotation and flow measurements of EI Eri using multi-site Doppler imaging during the MUSICOS 1998 campaign.

Findings

Weak solar-type differential rotation detected

Presence of tiny poleward meridional flow observed

Surface features mapped from time-series spectroscopic data

Abstract

We present time-series Doppler images of the rapidly-rotating active binary star EI Eri from spectroscopic observations collected during the MUSICOS multi-site campaign in 1998, since the critical rotation period of 1.947 days makes it impossible to obtain time-resolved images from a single site. From the surface reconstructions a weak solar-type differential rotation, as well as a tiny poleward meridional flow are measured.