NICER observation list: Target ID 356101

RX J0648.0-4418 is a peculiar binary consisting of an X-ray pulsar, and a hot subdwarf of O spectral type in a circular orbit. With a dinamically measured mass of 1.28 +/-0.05 M_sun, the nature of the X-ray source is still under debate. It may represent one of the heaviest White Dwarfs known, and also the fastest spinning one. Otherwise, it could represent a very light Neutron Star, with puzzling X-ray properties. Fast spin-up from this object has also been measured recently, interpreted in terms of a young, contracting WD. Here we propose for a NICER investigation of this target to characterize its timing and spectral behaviour.