In order to know the extent to which the phenomenon of Zodiacal light exists outside our solar system, Olivier Absil brought together a team of researchers (2) who studied some forty stars over a period of eight years. This is the EXOZODI Project.

But how can we observe this dust when we know that, even though it constitutes an important source of light, it is often masked by the light of the star? “Our observations were done by means of interferometry”, explains Olivier Absil. “The principle is simple: the light captured by six telescopes with a diameter of one meter separated from each other by a distance of 30 to 300 meters is focused on a single point thanks to mirrors that are located in vacuum tubes”. This set of six telescopes forms the CHARA array (Center for High Angular Resolution Astronomy) of Georgia State University, situated on Mount Wilson in California, making it possible to simulate a giant telescope with a diameter of nearly 330 m, and to distinguish details with an angle of only 200 microseconds, scarcely bigger than a football viewed from the moon! The light collected by the CHARA network is then recombined with the FLUOR instrument (Fiber Linked Unit for Optical Recombination), developed at Paris Observatory.

(2) Apart from Olivier Absil of the University of Liege, the international team that carried out this research included researchers from the Observatory of Paris (  Laboratory for Space Studies and Astrophysics Instrumentation LESIA – Observatory of Paris / CNRS / University of Pierre and Marie Curie / University Paris Diderot), the Observatory of Grenoble (OSUG – Institute of Planetology and Astrophysics of  Grenoble : CNRS / University Joseph Fourier) and the Observatory of Bordeaux (OASU – laboratory of Astrophysics of Bordeaux : CNRS / University of Bordeaux 1).