The corona and companion of CoRoT-2a. Insights from X-rays and optical spectroscopyS. Schröter, S. Czesla, U. Wolter, H. M. Müller, K. F. Huber and J. H. M. M. SchmittA&A, 532 (2011) A3DOI: https://doi.org/10.1051/0004-6361/201116961