We show that the compactness gap between black holes and neutron stars witnessed in general relativity can disappear in Hořava-Lifshitz (HL) gravity. Assuming a fermionic equation-of-state and solving the Tolman-Oppenheimer-Volkoff equation within the HL gravity framework, we find that there exists a minimum fermion mass $m_f^{(\min )}(q,y)$, above which the gap of the compactness between black hole and fermionic compact object vanishes, for a given deformation parameter $q$ of HL and interaction strength $y$ between fermions. Thus, in HL gravity, the mass and radius of an object found in the lower mass gap by LIGO-Virgo-KAGRA observations might not be able to classify it as a black hole or a neutron star. It is interesting to note that a fermion of mass $\sim 40\mathrm{GeV}$ can form a highly compact object of mass $\sim {10}^{-4}{M}_{\odot }$ and radius $\sim 1\mathrm{m}$. Such configurations may be regarded as speculative candidates for a subcomponent of cold dark matter. In addition, we find evidence for the existence of another class of compact objects whose compactness approaches that of black holes.

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• Alternative gravity theories
• Neutron stars & pulsars
• Primordial black holes
• Numerical simulations in gravitation & astrophysics