INSTABILITY OF A COLORED BLACK-HOLE SOLUTION

We analyze the stability of a black hole solution of the Einstein-Yang-Mills equations that was recently found numerically by Bizon, and which provides a counter example for the "no hair" conjecture for non-abelian black holes. In the framework of small time-dependent perturbations it is shown that there is at least one exponentially growing radial mode with the correct boundary conditions at the horizon and at infinity. © 1990.