Constraints on Estimation of Radius of Double Pulsar PSR J0737-3039A and Its Neutron Star Nuclear Matter Composition**Supported by the National Program on Key Research and Development Project under Grant No 2016YFA0400801, the National Natural Science Foundation of China under Grant Nos 11173034, 11673023 and 11364007, the Fundamental Research Funds for the Central University, the Key Support Disciplines of Theoretical Physics

Abstract

The aspect of formation and evolution of the recycled pulsar (PSR J0737-3039 A/B) is investigated, taking into account the contributions of accretion rate, radius and spin-evolution diagram (B–P diagram) in the double pulsar system. Accepting the spin-down age as a rough estimate (or often an upper limit) of the true age of the neutron star, we also impose the restrictions on the radius of this system. We calculate the radius of the recycled pulsar PSR J0737-3039 A ranges approximately from 8.14 to 25.74 km, and the composition of its neutron star nuclear matters is discussed in the mass-radius diagram.