| Abstract
| - New high-speed photometric observations of the rapidly oscillating Ap star HD 80316 suggest that its principal pulsation mode is an oblique dipole mode with a frequency of either 2251.68 or 2254.47 μHz (p = 7.4 min). Rotationally split frequency triplets give two choices for the rotation period, Prot = 2.085 ± 0.005 or 4.163 + 0.010 d, which agree with possible rotation periods derived independently from mean light observations. Both frequency triplet possibilities show the sum of the rotational inclination, i, and the magnetic obliquity, ², to be greater than 90±. This makes HD 80316 only the third roAp star, after HR 3831 and HD 6532, to have a polarity-reversing dipole pulsation. The two possible rotation periods are so close to multiples of 1 d−1 that alias problems in our single-site observations preclude a definite solution for the oscillations of this star. Further progress requires multisite observations, or long-term single-site observations to sample all rotation phases.
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