Absolute Astronomical Accelerometry

A project under development inFrance which will use the new spectroscopic technique of absolute accelerometry to search for extrasolar planets. The Emilie spectrograph at the Haute-Provence Observatory will be dedicated to this task.

A new technique is proposed, leading to two closely related instruments, the solar and stellar accelerometers. The principal fields of application are solar/stellar seismology and the search for extrasolar planets. The technique uses a variable path Fabry-Pérot interferometer whose channelled spectrum is constrained by a servo loop to track the Doppler shifted astronomical spectrum. Then a tunable laser tracks the interferometer. The ultimately measured quantity is the beat frequency between the tunable laser and a stabilized one.