  GW170817/GRB170817A, a short gamma-ray burst arising from a low-mass compact
object merger was the first multi-messenger discovery of a compact binary
system outside the local galactic neighborhood. From gravitational-wave
measurements, we know GW170817 has a wide range of plausible component masses,
depending also on less well-constrained properties such as the spin and tidal
deformability of the component stars. The kilonova light curve --- and hence
the total ejecta mass from a given source --- depends on the relative
contribution of dynamical ejecta and other sources such as disk winds.
Electromagnetic observations and model fitting of the ejecta properties from
the subsequent kilonova detection provided values of the ejecta mass from the
merger. These values, when combined with the gravitational-wave measurement
disfavors an equal-mass configuration, with the level of disagreement dependent
on the assumed amount of ejecta mass of dynamical origin. Within the confines
of our own galaxy, several binary neutron star systems along with measurements
of their component masses have been made. If those distributions are indicative
of a universal distribution, the joint measurement of the component masses of
GW170817 represents an outlier. This tension is not easily resolvable from
physical arguments, as the proposed pathways which form binary neutron stars do
not often produce very asymmetrical pairs. Even accounting for the uncertainty
associated with the total mass of the dynamical ejecta, this tension suggests
that the distribution of binary neutron star masses in the galaxy is not
indicative of those in other galaxies.
