NASA and the European Space Agency’s Hubble Space Telescope captured a blue bubble in outer space. Sparkling at the center of this image is a Wolf–Rayet star known as WR 31a, located about 30,000 light-years away in the constellation of Carina (The Keel).
A Wolf-Rayet star is a evolved star that originated with a mass over 20 times that of our Sun, but typically loses half its mass in less than 100,000 years by expelling material through a strong stellar wind. The expulsion of this material is thought to create bubbles like the one pictured above.
The distinctive blue bubble appearing to encircle WR 31a is a Wolf–Rayet nebula — an interstellar cloud of dust, hydrogen, helium and other gases. Created when speedy stellar winds interact with the outer layers of hydrogen ejected by Wolf–Rayet stars, these nebulae are frequently ring-shaped or spherical. The bubble — estimated to have formed around 20,000 years ago — is expanding at a rate of around 220,000 kilometers (136,700 miles) per hour.
Text source: European Space Agency
Image credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt
