Numerical simulations of tidal tails for the open cluster NGC 188

To aid future observations, we present the results of N-body simulations of tidal tails near the open cluster NGC 188. The simulated tidal tails stretch in both directions along the Galactic orbit of the cluster, extending to distances of at least 1 kpc. The cross-section of a tidal tail does not exceed 40-50 pc. On the sky, the number of tidal stars in the densest parts of a tail can reach a few percent of all visible stars only. The average dispersion of stellar velocities in the tidal tail is 1-3 km s-1. In velocity space, the tidal tails have a shape of a lengthy 'cold' star flux immersed in the 'hot' Galactic disc background. We provide the predicted position of the tidal tails and the expected distribution of radial velocities along the projection. The expected distribution of tidal star radial velocities has a large range (from -46 to +49 km s-1), thus underscoring the importance of predictions in future searches of tidal stars in open clusters. A preliminary search for tidal stars in the Two-Micron All-Sky Survey catalogue was not successful, indicating the need for a new CCD imaging to narrow down the number of possible former members of NGC 188 within the specified range of photometric and kinematic parameters.