Dwarf (Twin) Neutron Stars I: Did GW170817 Involve One?

Abstract

Dwarf neutron stars are stable twins of neutron stars but with a maximum mass less than that of neutron stars. Their existence brings into concordance the seemingly conflicting information on the size of neutron stars inferred from gravitational waves from GW170817, from the NICER mission, and from the PREX-II experiment. Their distinctive characteristics lead to rich and falsifiable predictions that are expected to be tested in the near future. If corroborated, the existence of dwarf neutron stars would substantially improve our understanding of the QCD phase diagram and offer valuable insights into the dark sector.