NGC 1360: The Robin's Egg Nebula

Explanation: This pretty nebula lies some 1,500 light-years away, its shape and color in this telescopic view reminiscent of a robin's egg . The cosmic cloud spans about 3 light-year s, 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 center 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 electron s 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 .

Celestial Surprise: What picture did APOD feature on your birthday? (post 1995)