* Astronomy

Title: Variability of the Ap Star HD9996
Authors: V.D. Bychkov, L.V. Bychkova, J. Madej, A.V. Shatilov

We present here new measurements of the longitudinal magnetic field (B_e) in the binary system HD9996, where the primary companion is an Ap star. Series of 63 B_e observations was obtained in years 1994-2011 with the 1m optical telescope of the Special Astrophysical Observatory (Russia). New magnetic data allowed us to refine the long-term magnetic period of HD9996 to P_mag=21.8 years. Compilation of archival photometric data showed the existence of long term variations of HD9996 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 summarise search for a short-term rotational period and the rotational line broadening in this star.

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