The science performances of the instrumental concept resulting from the CDF assessment study were estimated under the following assumptions, using instrument parameters summarized here. Realistic point-spread functions at various locations within the field were assumed, introducing a z=200 micron defocus in order to distribute the flux of any given star on 2x2 pixels. The star counts for various magnitudes were obtained using conservative estimates based on USNO-B1.0 catalogues. An average fraction of 60% main sequence stars down to mV=14 was assumed. The effects of saturation, smearing, and contamination by faint neighbours were taken into account in the final performance estimates. The PLATO field of view was assumed centred around a position at (210°,-60°) in ecliptic coordinates.
We assumed that 26 telescopes are used for the observation of stars with mV between 8 and 14, while the remaining two telescopes are devoted to the observation at higher cadence of bright stars in two colours, and for delivering depointing signal to the AOCS loop.
The estimated science performances, expressed in terms of the number of stars accessible for various levels of photometric noise, are given below:
