An optimized nulling ground based demonstrator for DARWIN: the ALADDIN proposal

We present here a ground-based mission which is optimized to study the exozodiacal dust around nearby solar-type stars. The objective is the same as the goal that led to the ESA phase A study for the GENIE nulling instrument at the VLTI: pave the way for future space missions dedicated to the spectroscopic IR characterization of exo-Earth atmospheres, by investigating one of the major, and least known, noise sources in the direct detection telluric exoplanets. An antarctic nuller is the optimal ground-based answer for this purpose, providing with relatively modest 1m apertures a capability that outperforms a pair of 8m telescopes on a temperate site.
The ALADDIN concept is an integrated Antarctic-based L-band nulling breadboard with relatively modest collectors (1m) and baseline (<40m). Because of its privileged location, this is sufficient to achieve a sensitivity (in terms of detectable zodi levels) better than GENIE at the VLTI, bringing it to threshold value (~30 zodis) identified to carry out the DARWIN precursor science. These estimations are based on a preliminary design study by Thalès Alenia Space and were obtained using the same simulation software as the one employed for GENIE. The integrated design enables top-level optimization and full access to the light collectors for the duration of the mission, while reducing the complexity of the nulling breadboard.