TOI-283 radial velocity and activity indices

We then performed a joint analysis of the photometric and RV data of this star, using Gaussian processes to model the systematic noise present in both datasets. We find that the host is a bright K-type star (d=82.4pc, Teff=5213+/-70K, V=10.4mag) with a mass and radius of M*=0.80+/-0.01M_{sun}_ and R*=0.85+/-0.03R_{sun}_. The planet has an orbital period of P=17.617-days, a size of Rp=2.34+/-0.09R_{Earth}_, and a mass of Mp=6.54+/-2.04M_{Earth}_.

With an equilibrium temperature of ~600 K and a bulk density of {rho}_p_=2.81+/-0.93g/cm^3^, this planet is positioned in the mass-radius diagram where planetary models predict H_2_O- and H/He-rich envelopes. The ESPRESSO RV data also reveal a long-term trend that is probably related to the star's activity cycle. Further RV observations are required to confirm whether this signal originates from stellar activity or another planetary body in the system.