Detecting exoplanets with extreme adaptive optics and a single-mode fibre fed spectrograph

A key technique used to detect and characterise exoplanets is Doppler spectroscopy. The technique involves measuring the amplitude of the periodic wavelength shift in the absorption lines of a star due to the physical wobble in the star brought on by the presence of an unseen orbiting planetary-mass companion. From the periodicity and the magnitude of the wobble velocity, it is possible to constrain parameters about the exoplanet such as mass, distance from the star, period and so on. This information is necessary for determining if the planet is likely to have the correct chemical composition in order to support life and if it is within the habitable zone (the region around a star where it is possible to support water in the liquid phase).