  The radio-emitting neutron star population encompasses objects with spin
periods ranging from milliseconds to tens of seconds. As they age and spin more
slowly, their radio emission is expected to cease. We present the discovery of
an ultra-long period radio-emitting neutron star, J0901-4046, with spin
properties distinct from the known spin and magnetic-decay powered neutron
stars. With a spin-period of 75.88 s, a characteristic age of 5.3 Myr, and a
narrow pulse duty-cycle, it is uncertain how radio emission is generated and
challenges our current understanding of how these systems evolve. The radio
emission has unique spectro-temporal properties such as quasi-periodicity and
partial nulling that provide important clues to the emission mechanism.
Detecting similar sources is observationally challenging, which implies a
larger undetected population. Our discovery establishes the existence of
ultra-long period neutron stars, suggesting a possible connection to the
evolution of highly magnetized neutron stars, ultra-long period magnetars, and
fast radio bursts
