PSR J1930–1852: a Pulsar in the Widest Known Orbit around Another Neutron Star

In the summer of 2012, during a Pulsar Search Collaboratory workshop, two high-school students discovered J1930–1852, a pulsar in a double neutron star (DNS) system. Most DNS systems are characterized by short orbital periods, rapid spin periods, and eccentric orbits. However, J1930–1852 has the longest spin period ( 185 ms) and orbital period ( 45 days) yet measured among known, recycled pulsars in DNS systems, implying a shorter than average and/or inefficient recycling period before its companion went supernova. We measure the relativistic advance of periastron for J1930–1852, (4) deg yr−1, which implies a total mass ( (4) ) consistent with other DNS systems. The constraints on place limits on the pulsar and companion masses ( and respectively). J1930–1852’s spin and orbital parameters challenge current DNS population models and make J1930–1852 an important system for further investigation.