Brane-world stars with solid crust and vacuum exterior

Abstract

The minimal geometric deformation approach is employed to show the existence of brane-world stellar distributions with vacuum Schwarzschild exterior, thus without energy leaking from the exterior of the brane-world star into the extra dimension. The interior satisfies all elementary criteria of physical acceptability for a stellar solution, namely, it is regular at the origin, the pressure and density are positive and decrease monotonically with increasing radius, finally all energy conditions are fulfilled. A very thin solid crust with negative radial pressure separates the interior from the exterior, having a thickness $Δ$ inversely proportional to both the brane tension $σ$ and the radius $R$ of the star, i.e. $Δ^{-1}\sim R\,σ$. This brane-world star with Schwarzschild exterior would appear only thermally radiating to a distant observer and be fully compatible with the stringent constraints imposed on stellar parameters by observations of gravitational lensing, orbital evolutions or properties of accretion disks.

20 pages, 6 figures. Improved version. To be published in Classical and Quantum Gravity