Simultaneous eROSITA and TESS observations of the ultra-active star AB Doradus J. H. M. M. Schmitt, P. Ioannidis, J. Robrade, P. Predehl, S. Czesla and P. C. Schneider A&A, 652 (2021) A135 Published online: 24 August 2021 DOI: 10.1051/0004-6361/202141379