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

摘要

We present time-series Doppler images of the rapidly-rotating active binarystar EI Eri from spectroscopic observations collected during the MUSICOSmulti-site campaign in 1998, since the critical rotation period of 1.947 daysmakes it impossible to obtain time-resolved images from a single site. From thesurface reconstructions a weak solar-type differential rotation, as well as atiny poleward meridional flow are measured.