Wednesday, Feb. 24, 2016: Wolf–Rayet star WR 31a (at center) lies about 30,000 light-years away in the constellation of Carina (The Keel). A blue bubble surrounds WR 31a consisting of a cloud of dust, hydrogen, helium, and other gases. This Wolf-Rayet nebula, as it’s known, forms when stellar winds interact with outer layers of hydrogen ejected by Wolf-Rayet stars, often forming ring or spherical shapes. The bubble, estimated at around 20,000 years old, expands at the extraordinary rate of around 137,000 miles (220,000 kilometers) per hour. Unfortunately, the life cycle of a Wolf-Rayet star lasts only (in relative terms) a few hundred thousand years. Image released Feb. 22, 2016.
— Tom Chao
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