Average motion of emerging solar active region polarities - II. Joy’s law H. Schunker, C. Baumgartner, A. C. Birch, R. H. Cameron, D. C. Braun and L. Gizon A&A, 640 (2020) A116 Published online: 26 August 2020 DOI: 10.1051/0004-6361/201937322