AIRS: the Infrared Spectroscopic Instrument of ESA M4 ARIEL mission

Abstract

The AIRS spectrometer will be used for Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, which will allow to measure atmospheric signals from the planet at levels of 10-100 part per million (ppm) relative to the star. This will require exquisite control of the full photon to digital codes acquisition chain bias along the long duration observation sequence. The prism-based spectrometer has been specifically designed to use anamorphosis of the prisms for circularizing the PSF of the elliptical primary mirror pupil in order to ensure optimal sampling and SNR. Because of the large dynamics of the stars the detector for the long waveband in the 7.80 µm range will need to be state-of-the-art and to be operated at 40-K. <P />