Orbital Eccentricity Effects on the Stochastic Gravitational Wave Background from Coalescing Binary Neutron Stars

Unresolved coalescing binary neutron stars in the Galaxy and beyond produce a stochastic gravitational wave background within the LISA frequency band, which can be potentially dangerous for possible detection of fundamentally more interesting relic cosmological backgrounds. Here we address the question what effects the unavoidable eccentricity of orbits of these systems should have on the properties of this backgrounds. In particularly, we examine starting from which frequency one-year observations with LISA can be secure from contamination by the noise produced by galactic binary neutron stars in eccentric orbits. We come to the conclusion that harmonics from such binaries do not contribute significantly above $\sim 10^{-3}$ Hz.