The convective-transition gap in 47 Tucanae with JWST

We report the detection of the convective-transition gap along the lower main sequence (MS) of the Galactic globular cluster (GC) 47,Tucanae using deep James Webb Space Telescope (JWST) observations. We analysed the stellar luminosity function (LF) in the vicinity of the gap location using two independent colour--magnitude diagrams (CMDs). In both cases, the LF is characterised by a narrow gap followed by a discontinuous increase in the stellar number counts. It presents an overall morphology that is qualitatively consistent with the results of previous studies. By modelling the observed LFs with an empirical likelihood model, we estimated the statistical significance of the observed feature. Additional JWST passbands exhibit similar signatures, providing further evidence to support the presence of a discontinuity.