A Blue Bubble 30,000 light-years away
NASA/ESA Hubble Space Telescope took this incredible image of a Wolf–Rayet star known as WR 31a, located about 30,000 light-years away in the constellation of Carina (The Keel).
The distinctive blue bubble appearing to encircle WR 31a is a Wolf–Rayet nebula of 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!
The image of WR 31a was snapped by the Wide Field Camera of Hubble’s Advanced Camera for Surveys (ACS).