Variability of the Ap Star HD 9996

We present here new measurements of the longitudinal magnetic field (B-e) in the binary system HD 9996, where the primary companion is an Ap star. Series of 63 B-e observations was obtained in years 1994-2011 with the 1-m optical telescope of the Special Astrophysical Observatory (Russia). New magnetic data allowed us to refine the long-term magnetic period of HD 9996 to P-mag = 21.8 years. Compilation of archival photometric data showed the existence of long-term variations of HD 9996 in time scale of 22-23 yr consistent with P-mag. We identify P-mag with the precession period of the primary Ap star and summarize search for a short-term rotational period and the rotational line broadening in this star.