Multi-wavelength observations of Proxima Centauri B. Fuhrmeister, S. Lalitha, K. Poppenhaeger, N. Rudolf, C. Liefke, A. Reiners, J. H. M. M. Schmitt and J.-U. Ness A&A, 534 (2011) A133 Published online: 20 October 2011 DOI: 10.1051/0004-6361/201117447