Characterization and formation of on-disk spicules in the Ca II K and Mg II k spectral lines Souvik Bose, Vasco M. J. Henriques, Jayant Joshi and Luc Rouppe van der Voort A&A, 631 (2019) L5 Published online: 05 November 2019 DOI: 10.1051/0004-6361/201936617