H12CN and H13CN excitation analysis in the circumstellar outflow of R Sculptoris M. Saberi, M. Maercker, E. De Beck, W. H. T. Vlemmings, H. Olofsson and T. Danilovich A&A, 599 (2017) A63 Published online: 01 March 2017 DOI: 10.1051/0004-6361/201629901