Paladini, C. ; Klotz, D. ; Sacuto, S. ; Lagadec, E. ; Wittkowski, M. ; Hron, J. ; Jorissen, A. ; Groenewegen, M. ; Kerschbaum, F. ; Verhoelst, T. ; Richichi, A. ; Olofsson, H.

published in Asymmetrical Planetary Nebulae VI Conference, pp. 68 (2014)

Abstract: Taking advantage of the results from the Herschel Mass-Loss of Evolved StarS (MESS) program we initiated a coordinated effort to study the same sample of Asymptotic Giant Branch (AGB) stars with different techniques. The aim is to characterise the geometry of the mass-loss process in AGB stars at different spatial scales. Being able to understand the shaping-mechanism on this evolutionary stage is crucial also for the successors. In this contribution we present the results of the VLTI/MIDI Large Program on AGB stars. While MESS probes the interface between the stellar atmosphere and the interstellar medium with MIDI we probe the onset of the stellar wind and of the dust formation. Our sample of 15 AGB stars cover different chemistry and variability type, spanning ideally the all AGB evolution. In our study we report spectral variability but not interferometric variability. This fact has implications on the size of the structures involved in the dust formation process. We detect asymmetric structures and elongation in a few cases, and we make an attempt to connect this with the evolution on the AGB.

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