The extended molecular envelope of the asymptotic giant branch star π1 Gruis as seen by ALMA - I. Large-scale kinematic structure and CO excitation properties
L. Doan, S. Ramstedt, W. H. T. Vlemmings, S. Höfner, E. De Beck, F. Kerschbaum, M. Lindqvist, M. Maercker, S. Mohamed, C. Paladini and M. Wittkowski