Prospects for the Study of Dust Making Wolf-rayet Binaries with the Vlti-spectro-imager (vsi)

The VLTI-Spectro-Imager (VSI) is a 2nd generation VLTI instrument under development (Malbet et al. 2008). The main improvement of VSI with respect to previous interferometric instruments (e.g. AMBER) is a significant enhancement of the imaging capability, thanks to the combination of 6 beams resulting in a significant spatial frequency gain. The science input will be further improved using the spectral dispersion of VSI, likely to reveal wavelength dependent structures in targets (e.g.. spectral lines produced in stellar winds of hot stars), and by high dynamic range observations that are expected to improve our understanding of many classes of objects (e.g. shells around evolved massive stars). In the context of the activities of the science group of the VSI consortium, many science topics have been considered, including a few devoted to massive stars (see Garcia et al. 2008).