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 (P-spin similar to 185 ms) and orbital period (P-b similar to 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, (omega) over dot = 0.00078 (4) deg yr(-1), which implies a total mass (M-tot = 2.59 (4) M-circle dot) consistent with other DNS systems. The 2 sigma constraints on M-tot place limits on the pulsar and companion masses (m(p) < 1.32 M-circle dot and m(c) > 1.30 M-circle dot respectively). J1930-1852's spin and orbital parameters challenge current DNS population models and make J1930-1852 an important system for further investigation.