Evolution of the magnetic field of Betelgeuse from 2009–2017 P. Mathias, M. Aurière, A. López Ariste, P. Petit, B. Tessore, E. Josselin, A. Lèbre, J. Morin, G. Wade, F. Herpin et al. (7 more) A&A, 615 (2018) A116 Published online: 24 July 2018 DOI: 10.1051/0004-6361/201732542