Spectroscopy of close visual binary components of the stable shell star 1 Delphini Jiří Kubát, Brankica Kubátová, Barbora Doležalová, Lubomir Iliev and Miroslav Šlechta A&A, 587 (2016) A22 Published online: 11 February 2016 DOI: 10.1051/0004-6361/201526414