2009MNRAS.396.1018H

We obtained 13 spectropolarimetric observations of the strongly magnetic rapidly oscillating Ap star HD154708 over 3 months with the multimode instrument FORS1, installed at the 8-m Kueyen telescope of the Very Large Telescope. These observations have been used for the determination of the rotation period of P = 5.3666±0.0007d. Using stellar fundamental parameters and the longitudinal magnetic field phase curve, we briefly discuss the magnetic field geometry. The star is observed nearly pole-on and the magnetic field geometry can be described by a centred dipole with a surface polar magnetic field strength B_d between 26.1 and 28.8kG and an inclination of the magnetic axis to the rotation axis in the range to.