The (2+1)-dimensional gravastars

We propose a new model of a gravastar in (2 + 1) anti-de Sitter spacetime. This new three-dimensional configuration has three different regions with different equations of state: [I] Interior: 0 <= r < r(1), rho = -p; [II] Shell: r(1) <= r < r(2), rho = p; [III] Exterior: r(2) < r, rho = p = 0. The outer region of this gravastar corresponds to the exterior (2 + 1) anti-de Sitter spacetime, popularly known as the BTZ spacetime. Like BTZ model, Lambda is taken to be negative, which at the junction turns out to be positive as required by stability of gravastar and mathematical consistency. After investigating the Interior spacetime, Shell and Exterior spacetime we have highlighted different physical features in terms of Length and Energy, Entropy, and Junction conditions of the spherical distribution. It is shown that the present model of charge-free gravastar in connection to the exterior (2 + 1) anti-de Sitter spacetime or the BTZ spacetime is non-singular. (C) 2011 Elsevier B.V. All rights reserved.