M82 X-2 is an X-ray pulsar located in the galaxy Messier 82, approximately 12 million light-years from Earth. It is exceptionally luminous, radiating energy equivalent to approximately ten million Suns. This object is part of a binary system : If the pulsar is of an average size, 1.4 M ☉, then its companion is at least 5.2 M ☉. On average, the pulsar rotates every 1.37 seconds, and revolves around its more massive companion every 2.5 days.