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Solar simulations and observations show that the detection of long-periodEarth-like planets is expected to be very difficult with radial velocitytechniques in the solar case because of activity. The inhibition of theconvective blueshift in active regions (which is then dominating the signal) isexpected to decrease toward lower mass stars, which would provide more suitableconditions. In this paper we build synthetic time series to be able toprecisely estimate the effects of activity on exoplanet detectability for starswith a wide range of spectral type (F6-K4) and activity levels (oldmain-sequence stars). We simulated a very large number of realistic time seriesof radial velocity, chromospheric emission, photometry, and astrometry. Webuilt a coherent grid of stellar parameters that covers a wide range in the(B-V, LogR'HK) space based on our current knowledge of stellar activity, to beable to produce these time series. We describe the model and assumptions indetail. We present first results on chromospheric emission. We find the averageLogR'HK to correspond well to the target values that are expected from themodel, and observe a strong effect of inclination on the average LogR'HK (overtime) and its long-term amplitude. This very large set of synthetic time seriesoffers many possibilities for future analysis, for example, for the parametereffect, correction method, and detection limits of exoplanets.

Activity time series of old stars from late F to early K. I. Simulating radial velocity, astrometry, photometry, and chromospheric emission