Confirming the Existence of Twin Stars in a NICER Way

Abstract We demonstrate that future radius measurements of the NICER mission have potential to reveal existence a strong phase transition in dense neutron star matter by confirming so-called twin stars, compact configurations with same mass but different radii. The latest constraints from for pulsars J0740+6620 as well J0030+0451 are discussed using relativistic mean field equations state varying stiffness, connected first-order quark matter. show solutions compatible new constraint located at radii below present NICER, serving smoking gun This scenario is realized if takes place stars first branch masses above 2 M ? .