THE DARWIN PROJECT - AN INFRARED NULLING INTERFEROMETER IN-SPACE

Angel and co-workers have proposed to detect exoplanets around nearby stars in the infrared (6-17 mu m) and to analyze their spectra, search ing for H2O, CO2, CH4, NH3, and O-3 spectral features. The presence or absence of CO2 would indicate either a strong similarity or differenc e with Solar telluric planet atmospheres. Water would indicate a habit able planet, and O-3 would reveal significant photosynthesis activity, due to the presence of carbon chemistry based life. Like these author s, we suggest an infrared nulling interferometer pointing to the star and working as a coronograph. Our main contribution is to propose an o bservatory made of four to five 1-meter class telescopes observing fro m about 4 to 5 AU to avoid the Solar Zodiacal Light (ZL) background at 10 mu m instead of four 8-meter ones observing from the Earth vicinit y. This allows the mission to be feasible in the near future. The conc ept, named DARWIN, is under consideration by the European Space Agency for its Horizon 2000 Plus program.