Irene Brito

General spherically symmetric elastic stars in relativity

The relativistic theory of elasticity is reviewed within the spherically symmetric context with a view towards the modeling of star interiors possessing elastic properties such as the ones expected in neutron stars. Emphasis is placed on generality in the main sections of the paper, and the results are then applied to specific examples. Along the way, a few general results for spacetimes admitting isometries are reviewed, and their consequences are fully exploited in the case of spherical symmetry relating them next to the the case in which the material content of the spacetime is some elastic material. Specific examples are provided satisfying the dominant energy condition and admitting a constitutive equation, including a static two-layer star ‘toy model’ consisting of an elastic core surrounded by a perfect fluid corresponding to the interior Schwarzschild solution matched to the vacuum Schwarzschild solution. This paper extends and generalizes the pioneering work by Magli and Kijowski (Gen Relat Gravit 24:139, 1992), Magli (Gen Relat Gravit 25:1277, 1993; 25:441, 1993), and complements, in a sense, that by Karlovini and Samuelsson in their interesting series of papers (Karlovini and Samuelsson in Class Quantum Grav 20:363, 2003; 21:1559, 21:4531, 2004).

Cylindrically symmetric static solutions of the Einstein field equations for elastic matter

The Einstein field equations are derived for a static cylindrically symmetric spacetime with elastic matter. The equations can be reduced to a system of two nonlinear ordinary differential equations and we present analytical and numerical solutions satisfying the dominant energy conditions. Furthermore, we show that the solutions can be matched at a finite radius to suitable Λ-vacuum exteriors given by the Linet-Tian spacetime.

Conformally flat sources for the Linet-Tian spacetime

We investigate the matching, across cylindrical surfaces, of static cylindrically symmetric conformally flat spacetimes with a cosmological constant

Conformal transformations in general relativistic elasticity

\Lambda

Friction Properties of Polyoxymethylene (POM) Materials in Dry and Lubricated Conditions

, satisfying regularity conditions at the axis, to an exterior Linet–Tian spacetime. We prove that for

Cylindrically symmetric inhomogeneous dust collapse with a zero expansion component

\Lambda \le 0