| Abstract
| - We revisit the rotation of P/Halley taking into account the most essential observational constraints, as well as the external torques affecting the nucleus, in particular the outgassing torque. We solve the dirty ice sublimation equations at each point of the sunlit surface, using, for the first time, the surface shape derived from the 1986 flybys imaging data. We assume that the nuclear surface is homogeneous in composition, thus reducing the number of model free parameters to one only: the dust-to-ice ratio on the surface. Our derived rotation model is a short-axis mode; it is consistent both with the 1986 nucleus imaging data, with the estimated non gravitational force, and with the observed time variations of the nucleus production rates. The outgassing torque results in a significant variation of the angular momentum vector -for the assumed nucleus density of 0.5 g/cm 3.
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