The PLATO–HARPSpol Activity and Magnetism Exploration (PHAME) Survey

We present the first results from the PLATO–HARPSpol Activity and Magnetism Exploration (PHAME) survey: a unique ground-based spectropolarimetric program providing magnetic and activity context for the upcoming ESA PLATO mission. With an allocation of nearly 550 hours of telescope time to date, PHAME began with a dedicated snapshot campaign using HARPSpol@ESO3.6m to assess the detectability of surface magnetic fields in PLATO LOPS2 targets, establishing activity levels and identifying stars suitable for Zeeman–Doppler Imaging (ZDI). A complementary ESPaDOnS@CFHT program covers the northernmost part of the LOPS2 field ($\sim$40 hours allocation to date). Building on this validated target selection, PHAME has progressed to a mapping phase (PHAME-MAP), where rotationally modulated observations constrain large-scale stellar magnetic topologies via ZDI. An approved extension (PHAME-MAP$^{2}$) adds a time-domain dimension through multi-epoch ZDI, enabling the study of magnetic and activity cycles. By combining activity diagnostics with surface magnetic field maps over yearly baselines, PHAME aims to establish a magnetic reference for F–G–K stars within the PLATO field. This reference will link stellar magnetism with PLATO’s planned asteroseismic inferences and enable tailored models of star–planet interactions. The magnetic legacy obtained by PHAME will also inform future atmospheric characterization of PLATO-discovered exoplanets with ANDES@ELT, where accurate knowledge of host-star activity and magnetism is essential for accurately interpreting high-resolution transmission spectra.