Number of eclipsing binaries vs. transiting planets: preparation of follow-up observations Tristan Guillot (OCA), Frédéric Pont, Maxime Marmier, Didier Queloz (Obs. Genève) & A. Garnier, F. Fressin, E. Matter, P. Mathias (OCA), M. Vannier (ESO), S. Aigrain (Cambridge), C. Moutou (LAM), M. Auvergne (LESIA)

25/05/2005CoRoTWeek82 Motivations Background eclipsing binaries (BEBs) represent a major source of confusion for planet detection –This is especially the case when looking for small planets (~10 -3 luminosity drop) We need numbers! –# of expected transiting planets –# of expected BEBs –Fraction of BEBs that can be discriminated directly from a lightcurve analysis (including the “color” information) –For the others, what are the observations that are most appropriate We need test cases! –List of events (with all the stars in the mask) –Realistic lightcurves with instrument noise

25/05/2005CoRoTWeek83 # events towards the gal. center background eclipsing binaries background planets target planets target binaries About 130 BeB 1 CCD only

25/05/2005CoRoTWeek84 COROTlux: Principle Create a synthetic stellar field Add double, triple stars Add planetary companions Create COROT masks Determine contributions to each mask For each mask, calculate 150 days lightcurve including: -Eclipses & transits -Stellar variability -Photon & instrumental noises

25/05/2005CoRoTWeek85 Ingredient 1: the stellar field Presently: randomly generated –Magnitude counts based on the Besançon model (BM) and direct observations –Mass-radius-luminosity relations: Previously used MS relations Now based on fits from a corrected BM Present calculations underestimate the crowding, overestimate the # of target stars / CCD –Giant stars are not included –Fields are much more homogeneous than in reality Future improvements: –Direct use of the star list generated by the BM Work in progress (E. Matar & P. Mathias) –Use real observations (e.g. data from M. Deleuil, C. Moutou, H. Deeg)

25/05/2005CoRoTWeek86 Ingredient 2: binaries & ternaries Presently: based on Duquennoy & Mayor (1991) –Distribution of orbits –Distribution of mass ratios Are the # of BeBs sensitive to these hypotheses? –Yes! Future improvements: –Test using the OGLE data (Work by F. Pont) –After launch: Use COROT data to check the models

25/05/2005CoRoTWeek87 Ingredient 3: the planets Mass-radius relations: –Quite uncertain: Can be fitted to the presently known transiting planets but depends on the presence of a core & its mass, & on tidal, atmospheric effects –This is an essential result to be obtained from COROT Distributions of orbits & masses: –1st possibility: use known radial velocity surveys results hence, consider only massive planets (Saturn mass) –2nd possibility: Known RV planets for large masses+ a large # of Uranus-sized planets (  -Ara like) Distribution of mass ratios –3rd possibility: Use theoretical predictions e.g. Ida & Lin (2003)

25/05/2005CoRoTWeek88 Outcome: a list of events What should be relatively accurate: –# of planets of the mass of Saturn and above –# of eclipsing binaries What we don’t know: –# of small planets (below Saturn’s mass) A list of events in the mask –Physical parameters to be included: Position and shape of the mask in the CCD For all stars with ∆m  5 to 10: –their position in the mask (or outside) –their magnitude –their color –their binarity Position within the mask –Needs to be combined to realistic instrumental noise –Test detection algorithms

25/05/2005CoRoTWeek89 A possible pipeline for preparatory follow-up work Preparatory observations of COROT fields (LAM, IAC...) Distributions of radii, BeBs, planetary transits...etc from known surveys (Geneva/ESA, OCA...) List of expected events (BeBs, transits...) (OCA, Geneva/ESA...) Add stellar noises (Cambridge, Italy) Add instrumental noises (LAM, LESIA) List of lightcurves (LAM) Test detection algorithms (LAM, Geneva/ESA, Cambridge, DLR, IAS, IAC, OCA...) Prepare follow-up observations (LAM, Geneva/ESA, Cambridge, DLR, IAS, IAC, OCA...)

Super Earth Sub-giants Giants

background eclipsing binaries target planets Fiducial case for binary distribution + Ida-Lin planet distribution

background eclipsing binaries target planets Pure gaussian binary distribution + RV planet distribution