Abstract

In the last ten years the technique of long-baseline interferometry at infrared wavelengths has allowed the inner astronomical units of numerous young stellar objects to be probed. These new observations, initially sizes measurements, have revealed the need for a profound revision of standard accretion disk paradigm at these angular scales. In the first part of the talk I will review the most recent observational advances in that field. These include spectrally resolved observations with the VLTI /AMBER and the first steps towards direct imaging of young disks at the spatial scales of planetary formation. These works point out the need for refined models of the complex interaction between the star, the mass loss phenomenon and the accretion disk. I will discuss the current observational limitations both in terms of image dynamics and sensitivity.

This will lead me, in a second part, to present the second generation VLTI instruments Gravity and VSI that will see the light between 2013 and 2016. I will briefly mention the technological innovations at the heart of there concepts that will help to overcome the current issues. These instruments will soon offer the european astronomical community with a unique tool to directly image protoplanetary worlds at the astronomical scale.