Tracking the sources of photons is a hobby of many astrophysicists. Some types of photons are tied so closely to particular phenomena that tracking their sources would help answer some larger questions in astrophysics itself. Photons on the "511 keV line" are one such type of photon, and they have been overrepresented near the galactic core, with no known source being prolific enough to create them. A new paper from Zachary Metzler and Zorawar Wadiasingh of the University of Maryland and NASA's Goddard Space Flight Center suggests one potential source - millisecond pulsar (MSP) binaries.