The PLATO’s catalogue of thousands of characterised planets and between 300,000 and ~1,000,000 high precision stellar light curves (depending on the final observing strategy) will provide the basis of a huge legacy for stellar and galactic science, which will be explored by the community in the years to come after the PLATO mission.

PLATO will provide a large catalogue of very well characterised stars. No other missions (actual or planned) will provide such a sample with the same accurate long-term photometric characterisation.

Planets around bright stars, detected and characterised by PLATO, will be ideal targets for spectroscopic studies to investigate their atmospheres and link them with the planetary bulk properties.

Observing further transits of large planets around suitably bright objects from the ground over long periods, well beyond the mission’s lifetime, will enable searches for planets or exomoons by TTVs and Transit Duration Variations (TDVs) over a very long time base.

During the mission RV follow-up to determine planet masses will focus on the most scientifically interesting targets; candidates detected by PLATO, but not confirmed by RV within the mission lifetime, will provide a wealth of targets for future mass determinations by the science community, resulting in thousands of further characterised planets.

Historically, the spectral classification of stars and the resulting Hertzsprung–Russell diagram (HR diagram) are based on hundreds of thousands of stellar spectra. It is well known how the HR diagram constituted, and still is, the basic tool for our understanding of stellar structure and evolution. Similarly, PLATO will allow identifying statistically robust relations among planetary and stellar parameters. For the first time it will be possible to properly classify planets and planetary systems via an in depth understanding of their structure, formation and evolution.