Guest Observers Programme

Members of the scientific community may participate in the PLATO mission by becoming Guest Observers (GOs) selected by ESA through calls for proposals. The calls will ask for complementary science programmes not covered by the PLATO core science objectives, and targeting objects within the PLATO sky fields defined by the Science Working Team (SWT), that is, without requiring dedicated repointing of the spacecraft. The duration of the proposed observations cannot exceed the observation durations of the corresponding fields. ESA will appoint a Time Allocation Committee (TAC) for the evaluation and selection of the proposals.

The first call will be issued nine months before launch, after the publication of the PLATO Input Catalogue (PIC) and of the prime sample. More open calls will be issued during the mission (once per year, TBC) at the discretion of ESA, following the advice from the SWT. At any given time, 8% of the science data rate (excluding calibration data) will be allocated to the GOs.This percentage will allow for an extended complementary science programme, while preserving the resources for an optimal observation of the core science targets. The total number of objects that may be observed with this allocation will range from thousands to tens of thousands, depending on the type of observations (e.g., imagettes or light curves) and sampling times requested.

GO programmes can contain targets that are part of the PIC, but not of the prime sample, which will be defined by the SWT before the first call. For targets in common with the PIC, access to the associated Level-0 and Level-1 data will be granted with the condition that the observations are exclusively used in relation with the science objectives of the proposal. Exploitation for complementary science of nonpublic PIC target data will only be carried out through approved GO programmes.

GO programmes can include the observation of Targets of Opportunity (ToO). GO programmes for ToOs may contain objects which can be identified in advance but which undergo unpredictable changes (e.g., recurrent novae), as well as objects that can only be identified in advance as a class (e.g., novae, supernovae, gamma ray bursts). The TAC will prioritise the ToOs with respect to on-going GO programmes, to permit the interruption of lower priority targets observations if required by the ToO. However, ToOs will be observed only on a best effort basis, if their observation can be implemented during the nominal mission cycle.

ESA will invite the GOs to provide their data and results, to make them accessible through the PLATO Science Archive.