Credit: NASA/ESA, Bruce Bal­ick (Uni­ver­sity of Wash­ing­ton), Jason Alexan­der (Uni­ver­sity of Wash­ing­ton), Arsen Hajian (U.S. Naval Obser­va­tory), Yer­vant Terz­ian (Cor­nell Uni­ver­sity), Mario Perinotto (Uni­ver­sity of Flo­rence, Italy), Patrizio Patri­archi (Arcetri Obser­va­tory, Italy)

Here is a new orna­ment for the Christ­mas tree. NGC 7009, or the Sat­urn Neb­ula, glows with hol­i­day light in this image from NASA’s Hub­ble Space Tele­scope. NGC 7009 is a plan­e­tary neb­ula. When a Sun-like star reaches the end of its life and has used up all of its hydro­gen fuel, it plumps up to become a red giant. Even­tu­ally, how­ever, the star throws off its outer lay­ers into space, cre­at­ing a bub­ble around a hot white dwarf. These bub­bles are called plan­e­tary neb­ula because in early tele­scopes they had a round shape like plan­ets. The bub­ble will keep on expand­ing and fac­ing into space over time. The white dwarf, just a hot cin­der, will also cool into a dark, warm lump of ash.

Explore the image. Can you find the white dwarf star in the cen­ter of the neb­ula? A football-shaped rim of dense gas, the lead­ing edge of the neb­ula’s bub­ble, traps green­ish gas inside. The neb­ula is all that remains of the for­mer star. Intense ultra­vi­o­let light from the cen­tral star excites mol­e­cules inside the gas cloud and causes it to glow. Dif­fer­ent col­ors mean dif­fer­ent elements.

Travel along the long part of the neb­ula. Out at the ends are red “han­dles” or “ansae.” These clouds were prob­a­bly the first parts of the neb­ula to be ejected by the star. They are con­nected to the neb­ula by long green­ish jets of material.

NGC 7009 is found about 1,400 light-years from Earth toward the con­stel­la­tion of Aquar­ius, the Water Bearer.

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