The Butterfly Nebula or NGC 6302 is a bipolar planetary nebula located in the constellation Scorpius. It is also known as the Nebula of the Insect or the Twins, and was first studied in 1907 by the American astronomer Edward Emerson Barnard, who drew and described it. It is at a distance of 3,400 light years from Earth.
It is a complex nebula formed by two iridescent lobes of material that extend outward from a central star system. From these lobes flow two huge jets of gas at speeds exceeding one million kilometers per hour.
These bright expanding gas lobes are the clear representation of the last stages of life of a star of low intermediate mass. After having expelled its outer layers, a remaining core remains exposed by illuminating those layers, which gives rise to the spectacular nebula of the Butterfly.
It is estimated that the central and dying star of the Butterfly Nebula reaches a surface temperature of about 250,000 degrees Celsius. These very high temperatures make the star shine brightly in ultraviolet light, but it cannot be seen directly because it is wrapped in a dense sector of dust. Recently molecular hydrogen has been detected in the dusty coating of this hot star.