The recent detection of gravitational waves and electromagnetic emissions from the binary neutron star merger GW170817 resulted in stringent limits concerning the masses and radii of the coalescing stars. These estimates complement ongoing measurements from pulsar timing and X-ray observations, including forthcoming NICER results, as well as theoretical limits stemming from neutron matter theory and condensed matter and nuclear experiments. There are important ramifications for the dense matter equation of state originating not only from these mass and radius measurements, but also from new lower and upper bounds to the maximum mass of neutron stars that can be inferred from observations. The properties and implications for nucleosynthesis of s190426c, a possible black hole-neutron star merger recently detected by the LIGO/Virgo Collaboration, are examined.