  Strange quark matter, which is composed of u, d, and s quarks, could be the
true ground of matter. According to this hypothesis, compact stars may actually
be strange quark stars, and there may even be stable strange quark dwarfs and
strange quark planets. The detection of the binary neutron star merger event
GW170817 provides us new clues on the equation of state of compact stars. In
this study, the tidal deformability of strange quark planets and strange quark
dwarfs are calculated. It is found that the tidal deformability of strange
quark objects is smaller than that of normal matter counterparts. For a typical
0.6 M$_\odot$ compact star, the tidal deformability of a strange dwarf is about
1.4 times less than that of a normal white dwarf. The difference is even more
significant between strange quark planets and normal matter planets.
Additionally, if the strange quark planet is a bare one (i.e., not covered by a
normal matter curst), the tidal deformability will be extremely small, which
means bare strange quark planets will hardly be distorted by tidal forces. Our
study clearly proves the effectiveness of identifying strange quark objects via
searching for strange quark planets through gravitational-wave observations.
