It is well known that static straight local cosmic strings coupled to gravity produce a spacetime with conical sections transverse to the axis of the string. We examine the effect of coupling local cosmic strings, not to standard Einstein gravity (GR), but to a Jordan-Brans-Dicke (JBD) theory of gravity. The new JBD metric is shown to be approximately that of the cone obtained in GR times a conformal factor of a small power of the radius. We examine the geodesics for this metric. All null geodesics are unchanged, but massive particles will have bound trajectories. The upper bound for these trajectories will be inside the cosmological horizon for particles moving considerably slower than the velocity of light with respect to the string.

• Received 25 May 1990

DOI:https://doi.org/10.1103/PhysRevD.42.2521