2017ApJ...842..105D

We report the identification of the optical counterpart to the companion of the millisecond pulsar J2317+1439. At the timing position of the pulsar, we find an object with g=22.96±0.05, r=22.86±0.04, and i=22.82±0.05. The magnitudes and colors of the object are consistent with a white dwarf (WD). Compared with WD cooling models, we estimate that it has a mass of 0.39_–0.10^+0.13M_☉, an effective temperature of 8077_–470⁺⁵⁵⁰ K, and a cooling age of 10.9 ± 0.3 Gyr. Combining our results with published constraints on the orbital parameters obtained through pulsar timing, we estimate the pulsar mass to be 3.4_–1.1^+1.4M_☉. Although the constraint on the pulsar mass is still weak, there is a significant possibility that the pulsar could be more massive than two solar masses.