Naked singularity of the Vaidya-de Sitter spacetime and cosmic censorship conjecture

We investigate the formation of a locally naked singularity in the collapse of radiation shells in an expanding Vaidya-de Sitter background. This is a chieved by considering the behaviour of non-spacelike and radial geodesics originating at the singularity. A specific condition is determined for the existence of radially outgoing, null geodesics originating at the singulari ty which, when this condition is satisfied, becomes locally naked. This con dition turns out to be the same as that in the collapse of radiation shells in an asymptotically flat background. Therefore we have established, at le ast for the case considered here, that the asymptotic flatness of the space time is not essential for the development of a locally naked singularity. O ur result then unequivocally supports the view that no special role be give n to asymptotic observers (or, for that matter, any set of observers) in th e formulation of the Cosmic Censorship Hypothesis.