Published online by Cambridge University Press: 12 April 2016
The ST3 mission will launch a space optical interferometer into heliocentric orbit, for observation of 50–100 sources on baselines of 40–200 m, during a time span of 3–4.5 months. The angular resolution in the 450–900 nm passband will be ≈ 500 microarcseconds. For Be stars, a velocity resolution of 50–100 km/s can be achieved by operating the interferometer in a Fourier Transform Spectrometer mode. This should allow spectrally resolved measurements of the brightness distribution in circumstellar disks, but will be limited to stars brighter than a visual magnitude of ≈ 5.