Simulating starspot activity jitter for spectral types F–M: realistic estimates for a representative sample of known exoplanet hosts

Stellar activity represents a serious limitation to exoplanet radial velocity (RV) searches. In fact, surface inhomogeneities due to magnetic activity such as spots produce distortions in the spectral line profiles and therefore spurious RV shifts (know as “jitter”) up to several m/s that drown small planet signals or undermine the accuracy of planetary characterisation. Modelling the spot-driven RV variability is therefore important to design efficient activity-filtering techniques and inform observing strategies.

Our aim is to characterise starspots and simulate the radial velocity curves they induce to determine typical jitter amplitudes for a representative sample of known host stars spanning between F and M spectral type.