Unfolding Properties of Mass Loss at the Tip of the Asymptotic Giant Branch

In the final stages of stellar evolution low- to intermediate-mass stars lose their envelope in increasingly massive stellar winds. Matter, which has been processed inside these stars, is thereby returned to the interstellar medium, and mass loss also determines properties of subsequent planetary nebulae. In order to obtain properties of winds at the tip of the asymptotic giant branch we observed weak halos of a set of planetary nebulae in the galactic disk. For this purpose we used the method of integral field spectroscopy together with a new dedicated data analysis method. In this presentation I will demonstrate the key concepts of our method and also highlight our results. The data shows that mass loss rates increase strongly in the final mass loss stage, and for several nebulae we derived a densely sampled and steeply increasing temperature gradient into the halo - indicating that the halo is not in thermal equilibrium.