There is a long standing issue with Gravistars, recent paper here: http://arxiv.org/abs/gr-qc/0509087 gives a good overview, and has links therein. One can understand that the 'Gravitational Vacuum Star', above has evolved from a certain paramiters contained in the above paper, for instance ordinary Stellar Stars, have their own intertwined/embedded processes, a [fusion-core] embedded within a [fission-outer shell[fusion-core]fission-outer shell] nuclear structure. The paper details 'gravistar signals' to be of a certain type. In this paper:http://arxiv.org/abs/gr-qc/0509090 they have extended also has a 'chosen' type of perturbations (waves). Can both have an underlaying common 'co-incedence' factor? And thus yet another interesting paper:http://arxiv.org/abs/gr-qc/0509088 shows an analytical model of a radiating star undergoing gravitational collapse with non-vanishing shear, interesting papers.