  We provide a systematic study of the isospin composition and
neutron-to-proton $\left( \frac{N}{Z} \right)$ ratio dependence of nuclear
short-range correlations (SRC) across the nuclear mass table. We use the
low-order correlation operator approximation (LCA) to compute the SRC
contribution to the single-nucleon momentum distributions for 14 different
nuclei from $A=4$ to $A=208$. Ten asymmetric nuclei are included for which the
neutrons outnumber the protons by a factor of up to 1.54. The computed momentum
distributions are used to extract the pair composition of the SRC. We find that
there is a comprehensive picture for the isospin composition of SRC and their
evolution with nucleon momentum. We also compute the non-relativistic kinetic
energy of neutrons and protons and its evolution with nuclear mass $A$ and
$\frac{N}{Z}$. Confirming the conclusions from alternate studies it is shown
that the minority species (protons) become increasingly more short-range
correlated as the neutron-to-proton ratio increases. We forge connections
between measured nucleon-knockout quantities sensitive to SRC and
single-nucleon momentum distributions. It is shown that the LCA can account for
the observed trends in the data, like the fact that in neutron-rich nuclei the
protons are responsible for an unexpectedly large fraction of the high-momentum
components.
