Detection of emission in the Si I 1082.7 nm line core in sunspot umbrae D. Orozco Suárez, C. Quintero Noda, B. Ruiz Cobo, M. Collados Vera and T. Felipe A&A, 607 (2017) A102 Published online: 21 November 2017 DOI: 10.1051/0004-6361/201731216