Astronomy Colloquium

After outlining the basics of our current understanding of the formation and evolution of extra-solar planetary systems, I briefly describe the three pathways used so far to tackle remaining open questions: the 'top-down' brown dwarf and the 'bottom-up' disk sciences, both bracketing the indirect/direct exoplanet detection/characterization efforts. As an illustration of a hybrid bottom-up/direct approach, I present the status of our adaptive optics (AO) survey of Spitzer/WISE debris disk stars with NIRC2@Keck, NACO@VLT, and PHARO@Palomar. This survey is as ambitious as it gets provided the current capabilities of AO instruments. Direct imaging has indeed up to now only scratched the surface of a huge parameter space, orthogonal to the very successful, yet indirect techniques. With the advent of extreme AO/wavefront control technologies and modern coronagraphy, second-generation facilities such as GPI, SPHERE, P3K, SCExAO are poised to break through the current contrast and inner working angle (IWA) wall. However, first-generation instruments still have a lot of untapped potential, that savvy upgrades can unleash, especially in the mid-IR (L/M/N bands), a scientifically key wavelength regime neglected by second-generation instruments. As a case in point, I present the development, deployment, and first science results of small IWA mid-IR vector vortex coronagraphs (VVC) at the VLT (NACO & VISIR), and LBT (LMIRCAM). I also review the scientific achievements of the P3K-PHARO near-IR VVCs (available since 2010), the status of on-going Palomar upgrades, and proposed plans for Keck, paving the way towards the extremely large telescopes (TMT, European ELT, and GMT). Finally, I discuss the results and implications of the successful 2-year VVC test campaign on the JPL high contrast imaging testbed (HCIT), performed within NASA's technology demonstration for exoplanet space-based missions (TDEM) framework. The VVC demonstrated contrast levels and inner working angles sufficient for imaging Earth-like and Super-Earth planets around M dwarfs with ELTs, as well as old Jupiter in reflected light with, e.g. a space-based coronagraphic probe, or explorer.