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We used the Atacama Pathfinder Experiment (APEX) telescope to search for CI1-0 (492.16GHz) emission towards 8 proplyds in NGC 1977, which is an FUVradiation environment two orders of magnitude weaker than that irradiating theOrion Nebular Cluster (ONC) proplyds. CI is expected to enable us to probe thewind launching region of externally photoevaporating discs. Of the 8 targetsobserved, no 3$\sigma$ detections of the CI line were made despite reachingsensitivities deeper than the anticipated requirement for detection from priorAPEX CI observations of nearby discs and models of external photoevaporation ofquite massive discs. By comparing both the proplyd mass loss rates and CI fluxconstraints with a large grid of external photoevaporation simulations, wedetermine that the non-detections are in fact fully consistent with the modelsif the proplyd discs are very low mass. Deeper observations in CI and probes ofthe disc mass with other tracers (e.g. in the continuum and CO) can test this.If such a test finds higher masses, this would imply carbon depletion in theouter disc, as has been proposed for other discs with surprisingly low CIfluxes, though more massive discs would also be incompatible with models thatcan explain the observed mass loss rates and CI non-detections. The expectedremaining lifetimes of the proplyds are estimated to be similar to those ofproplyds in the ONC at 0.1Myr. Rapid destruction of discs is therefore also afeature of common, intermediate UV environments.

An APEX search for carbon emission from NGC 1977 proplyds