Seminar: Earth 2.0 - How would an Earth-twin look like to PLATO?
Earth-sized extrasolar planets orbiting in the habitable zones of solar-like stars are prime targets to look for evidence supporting the existence of life on other planets in the Universe. However, until now neither radial velocity nor transit photometry techniques were precious enough to detect and characterise a potential signal stemming from an Earth-twin. With the launch of the PLATO (PLAnetary Transits and Oscillations of stars) satellite, planned in 2026, this might change. With its 26 cameras PLATO will continuously survey the sky and look for transiting exoplanets. To learn how to deal with the data the telescope will provide, we are already now simulating PLATO light curves. We use real data observed by the Solar Dynamic Observatory (SDO) to quantify the effects of stellar activity, especially of granulation, on the transit light curves. We then inject artificial transit events and provide this combination of stellar and planetary signals to the PlatoSim-simulator operated by the PLATO Mission Consortium. PlatoSim simulates the expected noise-model on a pixel basis and then integrates the flux observed across all pixels to end up with a final light curve product, which contains the stellar activity noise, the instrumental noise and the planetary signal. We then test a variety of popular detrending techniques to check how well they perform at retrieving the injected transit depth, with the aim of learning on how to best detrend real PLATO light curves. Finally, we provide a statical study on how stellar and planetary parameters like the stellar magnitude or the transit impact parameter affect the precision of the retrieved transit depths.