VI.D Achromatic Interferometery - Keck
The Keck Interferometer will have the following unique features relevant to the detection of the zodiacal emission around other stars:
High Strehl (phasing): Adaptive optics at each aperture to provide accurately phased wavefronts.
Phase-referenced operation (cophasing): Phase referencing, using high-bandwidth fringe tracking on an off-axis star or on the target star at a different wavelength, to cophase the interferometer and provide high sensitivity and high path-length stability.
Interferometric nulling between the two apertures reduces the dynamic range between the central star and the exozodiacal signal to enhance detection. Additional nulling interferometers at each aperture can be used to calibrate the background and the residual leakage of the central star. With this approach, detection of exozodiacal signals as small as 10- or even 1-zodi should be possible.
The Supplement section to this report compares achromatic single and dual-nulling operation of an instrument with the baseline characteristics of the Keck Interferometer.
Last updated March-06-1998