Stability of strange star crusts and strangelets

We construct strangelets, taking into account electrostatic effects, including Debye screening, and arbitrary surface tension σ of the interface between vacuum and quark matter. We find that there is a critical surface tension σcrit below which large strangelets are unstable to fragmentation and below which quark star surfaces will fragment into a crystalline crust made of charged strangelets immersed in an electron gas. We derive a model-independent relationship between σcrit and two parameters that characterize any quark matter equation of state. For reasonable model equations of state, we find σcrit typically of order a few MeV/fm2. If σ≤σcrit, the size-distribution of strangelets in cosmic rays could feature a peak corresponding to the stable strangelets that we construct.