SPHERICALLY SYMMETRICAL COLLAPSE OF AN ANISOTROPIC FLUID BODY INTO ANEXOTIC BLACK-HOLE

The classical gravitational equations of Einstein are investigated for an anisotropic fluid body in the case of spherical symmetry. An equat ion of state T(4)(4) +k(2)T((1))((1))=0 is imposed. The junction condi tions [T-b(a)]n(b)=0 Of Synge are required to be satisfied on the boun dary of the fluid body. A class of exact, analytical solutions dependi ng on four parameters is obtained. The solutions satisfy the equation of state and the weak energy conditions prior to the collapse of the b oundary inside the event horizon. However, in the interior of the even t horizon, the matter undergoes a transition into an exotic state. A p ortion of the fluid turns tachyonic with T-44<0, a second portion has complex eigenvalues for [T-b(a)], and a third part has signature + 4. (C) 1997 American Institute of Physics.