THE WHITE DWARF COMPANION OF A 2 Msun NEUTRON STAR

We report the optical discovery of the companion to the 2 Msun millisecond pulsar PSR J1614-2230. The optical colors show that the 0.5 Msun companion is a 2.2 Gyr old He-CO white dwarf. We infer that M-dot during the accretion phase is <10-2 M-dotedd. We show that the pulsar was born with a spin close to its current value, well below the rebirth line. The spin-down parameters, the mass of the pulsar, and the age of the system challenge the simple recycling model for the formation of millisecond pulsars.