HD 178892 – a cool Ap star with extremely strong magnetic field T. Ryabchikova, O. Kochukhov, D. Kudryavtsev, I. Romanyuk, E. Semenko, S. Bagnulo, G. Lo Curto, P. North and M. Sachkov A&A, 445 3 (2006) L47-L50 Published online: 03 January 2006 DOI: 10.1051/0004-6361:200500222