  The strong interactions at low energy scales determine the state of the
supranuclear matter in the pulsar-like compact objects. It is proposed that the
bulk strong matter could be composed of strangeons, which are quark clusters
with a nearly equal number of three light-flavor quarks. In this work, to
characterize the strong-repulsive interactions at short distances and the
non-relativistic nature of the strangeons, the Lennard-Jones model is used to
describe the equation of state (EoS) of strangeon stars (SSs). We investigate
the static, the slowly rotating, and the tidally deformed SSs in detail. The
corrections resulted from the finite surface densities are considered crucially
in the perturbative approaches. We also study the universal relations between
the moments of inertia, the tidal deformabilities, and the quadrupole moments.
Those results are ready to be used for various purposes in astrophysics, and
possible constraints from contemporary observations on the parameter space of
the Lennard-Jones model are discussed. Future observations of the pulsars'
radio signals, the X-ray emissions from the hot spots on the surface of the
stars, and the gravitational waves (GWs) from binary mergers can give tighter
constraints or even verify or falsify the existence of SSs.
