Ground-Based Photometric Follow-up for Exoplanet Detections with the PLATO Mission

Detections of transiting planets from the upcoming PLATO mission are expectedto face significant contamination from contaminating eclipsing binaries,resulting in false positives. To counter this, a ground-based programme toacquire time-critical photometry is pursued. Its principal aim is to obtaintime-series observations of the planet candidate and its surrounding stars atthe times of expected transits. This programme is part of the PLATOGround-based Observations Programme, which also covers spectroscopic andimaging observations. The current photometric follow-up programme is assemblingthe required observational resources, executing benchmark observations, anddefining strategies for the observations and their reporting. Post-launch, itwill focus on coordinating photometric data collection and analysis, and willupdate candidate statuses in the PLATO follow-up database. Its work packagesare outlined, covering specific tools, citizen contributions, standard andmulti-colour observations, secondary eclipses, and reprocessing of archivalphotometry. Ground-based follow-up photometry will likely concentrate onlonger-period candidates, given that false positives of short-period candidateswill likely become identifiable in timeseries available from GAIA in the nearfuture. Geographical considerations for follow-up observations from the firstPLATO long-observation field LOPS2 are outlined, which lies in the southernhemisphere, with later fields expected to be more suitable for northernobservers.