Generic thin-shell gravastars
  We construct generic spherically symmetric thin-shell gravastars by using the cut-and-paste procedure. We take considerable effort to make the analysis as general and unified as practicable; investigating both the internal physics of the transition layer and its interaction with "external forces" arising due to interactions between the transition layer and the bulk spacetime. Furthermore, we discuss both the dynamic and static situations. In particular, we consider "bounded excursion" dynamical configurations, and probe the stability of static configurations. For gravastars there is always a particularly compelling configuration in which the surface energy density is zero, while surface tension is nonzero. 
Prado Martin-Moruno (Victoria University of Wellington), Nadiezhda   Montelongo Garcia (CINVESTAV, IPN, Universidade de Lisb...
gr-qc astro-ph.HE hep-th