Star-planet interactions - II. Is planet engulfment the origin of fast rotating red giants? Giovanni Privitera, Georges Meynet, Patrick Eggenberger, Aline A. Vidotto, Eva Villaver and Michele Bianda A&A, 593 (2016) A128 Published online: 05 October 2016 DOI: 10.1051/0004-6361/201628758