Is a classical description of stable non-BPS D-branes possible?

We study the classical geometry produced by a stack of stable (i.e., tachyo n-free) non-BPS D-branes present in K3 compactifications of type IT string theory. This classical representation is derived by solving the equations o f motion describing the low-energy dynamics of the supergravity fields whic h couple to the non-BPS state. Differently from what expected, this configu ration displays a singular behaviour: the space-time geometry has a repulso n-like singularity This fact suggests that the simplest setting, namely a s et of coinciding non-interacting D-branes, is not acceptable. We finally di scuss the possible existence of other acceptable configurations correspondi ng to more complicated bound states of these non-BPS branes. (C) 2000 Elsev ier Science B.V. All rights reserved.