Cotton Candy Butterfly

Credit: Sun Kwok and Kate Su (Uni­ver­sity of Cal­gary), Bruce Hriv­nak (Val­paraiso Uni­ver­sity), and NASA

The moment cap­tured by NASA’s Hub­ble Space Tele­scope of the Cot­ton Candy Neb­ula is a fleet­ing one. The Cot­ton Candy Neb­ula shows the begin­ning stages of the trans­for­ma­tion from red giant to plan­e­tary neb­ula. Astronomers call this stage a proto-planetary neb­ula and it lasts only about 1,000 years.

A star starts to die when it exhausts its ther­monu­clear fuel of hydro­gen and helium. The star then bal­loons in size becom­ing brighter but also cooler. As a red giant, the star begins to puff shells of gas into space. We see these bub­bles of gas as con­cen­tric rings seen around the star. Even­tu­ally all that is left inside the glow­ing, expand­ing shell of gas is a hot white dwarf. Butterfly-shaped wings of gas and dust are com­mon around these stars. Fast stel­lar winds blow­ing from the white dwarf over­take and bust through the bubble-like cocoon. The result­ing neb­ula emerges. After a few hun­dred years, intense ultra­vi­o­let radi­a­tion com­ing from the cen­tral star will ener­gize the gas pre­vi­ously expelled and cause the entire neb­ula to glow.

The Cot­ton Candy Neb­ula, or IRAS 17150–3224, is found toward the con­stel­la­tion of Scor­pius, the Scor­pion.