Properties of the inner penumbral boundary and temporal evolution of a decaying sunspot M. Benko, S. J. González Manrique, H. Balthasar, P. Gömöry, C. Kuckein and J. Jurčák A&A, 620 (2018) A191 Published online: 17 December 2018 DOI: 10.1051/0004-6361/201834296