We report the optical discovery of the companion to the 2 M_sun millisecond pulsar PSR J1614-2230. The optical colors show that the 0.5 M_sun companion is a 2.2 Gyr old He-CO white dwarf. We infer that $\dot{ M}$ during the accretion phase is <10^{ -2}\dot{ M}_{ edd}. 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.
Categories: astro-ph.SR