The quest for extrasolar planets has become, over the last decade, one of the main scientific drivers for numerous instrumental initiatives worldwide. Both at ESA and NASA, space-based missions (resp. DARWIN and Terrestrial Planet Finder, hereafter TPF) are currently being designed to directly detect photons from Earth-like planets at mid-infrared wavelengths (e.g. Fridlund, 2004 AdSpR 34). However, as recognised by the space agencies, the presence of warm dust, in the form of an exozodiacal cloud in the habitable zone around nearby stars, might significantly compromise the ability of these missions to reach their goal. Yet, our current knowledge of dust within a few astronomical units around nearby solar-type stars is largely insufficient to feed the DARWIN/TPF design studies with realistic numbers, and the solar systemzodiacal cloud is by default systematically used as a reference.

Preliminary ground-based observations conducted by our team recently showed that exozodiacal disks may in fact show structures and brightness levels that significantly depart from the solar system
case. Ongoing design studies of DARWIN-like missions are thus based on assumptions on the exozodiacal emission levels which are not representative of the diversity of dust clouds around nearby stars. We therefore deem very timely to start investing significant efforts into intensive modeling and characterisation of exozodiacal disks, in an attempt to uncover possible commonalities and diversities between them and the zodiacal cloud in our Solar System.

Our team workshops will focus on the investigation of extrasolar analogs of the zodiacal cloud in the context of planet detection with future space-based missions such as DARWIN, with a final goal to identify the dominant source of dust production, and to develop a software tool capable of (1) interpreting the currently ongoing observations of exozodiacal dust and (2) predicting the structure and level of circumstellar dust that can be expected around the DARWIN target stars. To this end, we will bring together specialists in extrasolar dust disks and in the Solar System’s zodiacal cloud, with the required expertise in modeling, observations, laboratory experiments, instrumentation and space missions. These workshops are intended to facilitate existing and trigger new collaborative projects between the team members and provide a stimulating environment for new ideas.

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