Mitigating effects of stellar activity in RV using SCALPELS

After the detection of exoplanets using TESS, a major hurdle in the mass characterisation of these bodies with follow-up radial velocity(RV) observations is the contamination due to spurious stellar activity signals, as it is challenging to differentiate between a signal induced by stellar activity and a planet. A new algorithm, SCALPELS, has been developed to separate  RV Doppler shifts caused by the orbital motion of planets from the apparent RV variations caused by the spectral line-shape variability aroused by stellar activity. This method is effective in reducing the uncertainty arising from the apparent RVs due to stellar variability, and hence enabling the detection of low-mass exoplanets signals in data from active stars. 

Here we present results obtained from the application of SCALPELS to the RV data of Sun and an active, exoplanet hosting star. The results show the efficiency of this approach in correcting for confusing stellar activity signals and hence allowing more accurate mass characterisation by improving the fidelity of RV measurements. Overall, this would result in a significant improvement in the community's ability for precise follow-up characterisation of exoplanet systems detected by TESS.