Astronomy Picture of the Day

Explanation: This pretty nebula lies some 1,500 light-years away, its shape and colour in this telescopic view reminiscent of a robin's egg. The cosmic cloud spans about 3 light-years, nestled securely within the boundaries of the southern constellation of the Furnace (Fornax). Recognized as a planetary nebula, egg-shaped NGC 1360 doesn't represent a beginning, though. Instead, it corresponds to a brief and final phase in the evolution of an aging star. In fact, visible at the centre of the nebula, the central star of NGC 1360 is known to be a binary star system likely consisting of two evolved white dwarf stars, less massive but much hotter than the Sun. Their intense and otherwise invisible ultraviolet radiation has stripped away electrons from the atoms in their mutually surrounding gaseous shroud. The blue-green hue inside of NGC 1360 seen here is the strong emission produced as electrons recombine with doubly ionized oxygen atoms.