Talk abstract details

We present a general three-dimensional model of multipolar planetary nebulae (PNe). By rotating to different viewing angles and adjusting the angles between the multiple lobes, we demonstrate that the model is able to produce HST H$alpha$ images of 20 multipolar young PNe, e.g. NGC 6881. Though this model only considers the geometrical projection effects, it significantly unifies the selected PNe and can be considered as a first-order fundamental model of the "multipolar" morphological class. This kind of model reduces complexity and is essential to pursuing of the shaping mechanism. Further discussions based on the model parameters include the spectral energy distributions (SEDs) and the chemical compositions which reflect the evolutionary status of the PNe. In addition, we illustrate that under some special conditions, i.e. in certain viewing angles, it will be hard to imagine that the projected image originates from a multipolar model. More evolved cases such as NGC 6072 will also be compared.