This stunning image reveals the remnants of a Supernova and contains within it a tale of remarkable survival; a star that endured being closer to one of the most powerful explosions in the universe than we are to the sun, and will one day undergo a similar experience itself.
The image combines data collected by the Chandra X-Ray Observatory (purple) and ground based telescopes (yellow). This particular remnant, known as DEM L241 is of interest both because the explosion was so recent the gasses thrown off remain hot enough to be a bright X-ray emitter, and because a likely companion star has been detected, only the third such example known.
Davies, Elliot and Meaburn mapped DEM L241 in 1976, with its name taken from the initial letters of theirs. In 2012 Fredrick Seward of the Smithsonian Astrophysical Observatory detected an object that is bright in both the X-Ray part of the spectrum and in visible light and appears to orbit the supernova remnant once every ten days. This was concluded to be an O-type star that survived the supernova explosion.
For the supernova precursor to burn out before its companion it must have been larger, having a mass at least 25 times that of the sun and most likely around 40 times. Seward's paper notes, “It is therefore possible that the compact object, which we have assumed to be a neutron star, could actually be a black hole.” Interestingly, all known black holes are either at least 50 times brighter than this object, or more than a 100 times fainter in the X-Ray spectrum. If the object at the heart of DEM L241 is in fact a black hole it will be the first observed to fill this enormous brightness gap.
The dynamics of the system mean that the companion star would be losing mass to the black hole or neutron star it orbits. Nevertheless, the companion is so large that even with this loss of material it will eventually experience a supernova explosion itself. Once this occurs the system will be made up of either two neutron stars in orbit around each other, one neutron star orbiting a black hole, or even two black holes in orbit, forming a sort of celestial Scylla and Charybdis for future Ulysses to navigate around.