1. PLAnetary Transits and Oscillations of stars Claude CATALA Observatoire de Paris, LESIA http://www.oact.inaf.it/plato/PPLC/Home.html Main Science Requirements

2. PLATO target samples > 20,000 bright (~ m V ≤11) cool dwarfs/subgiants (>F5V&IV): exoplanet transits AND seismic analysis of their host stars AND ultra-high precision RV follow-up noise < 2.7 10 -5 in 1hr for 3 years > 245,000 cool dwarfs/subgiants (~ m V ≤13) exoplanet transits + RV follow-up >1,000 very bright (m V ≤8) cool dwarfs/subgiants for 3 years >3,000 very bright (m V ≤8) cool dwarfs/subgiants for >5 months exoplanets around bright and nearby stars Main focus of PLATO: Bright and nearby stars !! PLATO… is watching you ! noise < 8.10 -5 in 1hr for 3 years > 5,000 nearby M-dwarfs (m V ≤15) noise < 8. 10 -4 in 1hr for 3 years + > 5,000 for 2-5 months + lists of additional targets presenting specific interest

3. 8.0 x 10 -5 in 1 hr for marginal transit detection (faint targets) 1 R  planet transiting a solar-like star at 1 AU - mean of 3 transits Noise level requirements for PLATO 2.7 x 10 -5 in 1 hr for high S/N transit measurement: also required for seismic analysis noise = 2.7 x 10 -5 in 1 hr noise = 4.0 x 10 -5 in 1 hr noise = 6.2 x 10 -5 in 1 hr noise = 8.0 x 10 -5 in 1 hr

4. Noise requirements: seismic analysis ≤ 2.7 x 10 -5 in 1 hr frequency (  Hz) power (ppm 2 /  Hz) CoRoT HD 49385 m V = 7.4 137 days PLATO equivalent m V = 9.6 same data noise 2.7 x 10 -5 in 1 hr PLATO equivalent m V = 10.8

5. Observation of consecutive transits duty cycle ≥ 95% so that probability to see at least 3 consecutive transits ≥ 85% N=1 transit N=2 N=3 N=10 85% 95% - duty cycle  - duration so that at least 3 consecutive transits can be seen for planets at inner edge of habitable zone probability to see N successive transits p N =  N 2 to 3 years >2 months for the study of close-in planets

6. Photon noise dominated instrument shot noise + readout noise + background noise + jitter + digitization noise 27 ppm 80 ppm 800 ppm fast cam 8 cam 16 cam 24 cam32 cam jitter/confusion + background photon noise photon noise limited up to m V =11 Requirement = all non photonic sources of noise < 1/3 photon noise at m V =11 ≤ 0.2 arcsec≤ 40 electrons

7. Colours Provide colour information for brightest stars, in order to help oscillation mode identification The two fast cameras will observe through broadband filters : 2-colour photometry

8. Performances as a function of noise level as a function of magnitude PLATO (4300 deg 2 )20,000 deg 2 KEPLER (100 deg 2 ) noise level (ppm/√hr) nb of cool dwarfs & subgiants long monitoring mVmV nb of cool dwarfs & subgiants incl. step&stare nb of cool dwarfs & subgiants mVmV 2720,1509.3 - 10.880,4001,30011.2 80292,00011.6 - 12.91,000,00025,00013.6 1,32683,315308 60,27511180,0001,30011 20,000 245,000 1,000 3,000