Measuring precise radial velocities on individual spectral lines

Context. To enable radial velocity (RV) precision on the order of ~0.1 m s −1 required for detection Earth-like exoplanets orbiting solar-type stars, main obstacle lies in mitigating impact stellar activity. Aims. This study investigates dependence derived RVs with respect to formation temperature spectral line segments. Methods. Using synthesis, we computed below which 50% emergent flux originates each observed wavelength point unblended lines. We then constructed RV time series different ranges using template matching. Results. With HARPS-N solar data and HARPS α Cen B measurements, demonstrate intervals prominent activity that activity-induced signal has amplitude periodicity depending range considered. compare measurements simulated contributions from active surface regions seen simultaneous images, find suppression convective motion is dominant effect. Conclusions. From a carefully selected set lines, are able measure at various temperatures ranges. strongly correlate effect segments formed hotter At cooler temperatures, exhibit oppositely directed variations compared average stronger anticorrelations chromospheric emission.