HD 20794: A G6V star with 2 Super-Earths, combined analysis of ESPRESSO and HARPS

Bright nearby stars are relevant targets for RV follow-up. The large angular separation between planets and their host stars will make it feasible to study these systems with future instrumentation for high contrast direct imaging such as the ANDES spectrograph for ELT, the HabEx or LUVOIR Nasa Missions, and the ESA LIFE mission. Among nearby stars, solar-type stars are of particular interest as they allow us to study the architecture and evolution of planetary systems born in similar environments to our own. HD 20794 is a G6 star known for hosting a multi-planetary system. According to the literature, the system is composed of 4 planets, with orbital periods spanning a range between 18 and 147 days and minimum masses between 2.4 and 4.8 Earth masses. The results were achieved by analyzing more than 10 years of HARPS observations. This star is one of the most stable targets of HARPS in the neighborhood of the Sun. We present here an updated analysis of this star. In our analysis, we used 4 years of observations made with the ESPRESSO spectrograph combined with the HARPS data reprocessed with the new YARARA pipeline. This analysis confirms the great stability of the star over long timescales with an RMS of 1.16 m/s over more than 17 years. We perform a state-of-the-art analysis of the RV data combined with the activity indicators to obtain the most refined model to date for the planetary and stellar components of the data.