A ring in a shell: the large-scale 6D structure of the Vela OB2 complex T. Cantat-Gaudin, M. Mapelli, L. Balaguer-Núñez, C. Jordi, G. Sacco and A. Vallenari A&A, 621 (2019) A115 Published online: 17 January 2019 DOI: 10.1051/0004-6361/201834003