  The next observing runs of advanced gravitational-wave detectors will lead to
a variety of binary neutron star detections and numerous possibilities for
multi-messenger observations of binary neutron star systems. In this context a
clear understanding of the merger process and the possibility of prompt black
hole formation after merger is important, as the amount of ejected material
strongly depends on the merger dynamics. These dynamics are primarily affected
by the total mass of the binary, however, the mass ratio also influences the
postmerger evolution. To determine the effect of the mass ratio, we investigate
the parameter space around the prompt-collapse threshold with a new set of
fully relativistic simulations. The simulations cover three equations of state
and seven mass ratios in the range of $1.0 \leq q \leq 1.75$, with five to
seven simulations of binary systems of different total mass in each case. The
threshold mass is determined through an empirical relation based on the
collapse-time, which allows us to investigate effects of the mass-ratio on the
threshold mass and also on the properties of the remnant system. Furthermore,
we model effects of mass ratio and equation of state on tidal parameters of
threshold configurations.
