Hi-5 is a high-contrast (or high dynamic range) infrared imager project for the VLTI.
Its main goal is to characterize young extra-solar planetary systems and exozodiacal
dust around southern main-sequence stars. In this paper, we present an update of the
project and key technology pathways to improve the contrast achieved by the VLTI.
In particular, we discuss the possibility to use integrated optics, proven in the
near-infrared, in the thermal near-infrared (L and M bands, 3-5 p.m) and advanced
fringe tracking strategies. We also address the strong exoplanet science case (young
exoplanets, planet formation, and exozodiacal disks) offered by this wavelength regime
as well as other possible science cases such as stellar physics (fundamental parameters
and multiplicity) and extragalactic astrophysics (active galactic nuclei and fundamental
constants). Synergies and scientific preparation for other potential future instruments
such as the Planet Formation Imager are also briefly discussed.
