Proxima Cen ESPRESSO RV and FWHM

This small, low-mass, mid M dwarf is known to host an Earth-mass exoplanet with an orbital period of 11.2 days within the habitable zone, as well as a long-period planet candidate with an orbital period of close to 5yr. We report on the analysis of a large set of observations taken with the ESPRESSO spectrograph at the aimed at a thorough evaluation of the presence of a third low-mass planetary companion, which started emerging during a previous campaign.

Radial velocities (RVs) were calculated using both a cross-correlation function (CCF) and a template matching approach. The RV analysis includes a component to model Proxima`s activity using a Gaussian process (GP). We use the CCF's full width at half maximum to help constrain the GP, and we study other simultaneous observables as activity indicators in order to assess the nature of any potential RV signals.