Abstract

One of the challenges over the next decade is to find a reliable methodology to measure the mass of low-(Earth) mass exoplanets with orbital periods more similar to that of our own Earth. One method is to use the radial velocity technique which uses the shift of stellar spectral lines relative to a stable calibration source; from this the presence and masses of planetary bodies in orbit about a star can be deduced. The difficulty lies in reliably retrieving a low amplitude RV signal buried within the stellar variability noise. To address this problem we are proposing a “Terra Hunting Experiment” using a close-copy of the HARPS spectrograph installed on the 2.5m Isaac Newton Telescope (INT) in La Palma. The experiment will collect daily RV measurements on a sample of our brightest solar-type stars; a long series of daily sampled data will reduce signal aliases and improve the retrieval process for low amplitude signals. I will present an overview of the planned instrument (HARPS3), the rationale behind the experiment and a description of the proposed survey programme.