The emission of gravitational waves is studied for a system of massive
objects interacting on hyperbolic orbits within the quadrupole approximation
following the work of Capozziello et al. Here we focus on the derivation of an
analytic formula for the energy spectrum of the emitted waves. We checked
numerically that our formula is in agreement with the two limiting cases for
which results were already available: for the eccentricity {\epsilon} = 1, the
parabolic case whose spectrum was computed by Berry and Gair, and the large
{\epsilon} limit with the formula given by Turner.Comment: 9 pages, 4 figures, Accepted for publication in Physical Review
