Wolf-Rayet Star WR 31a Blows Hubble a Bubble

An interstellar cloud of dust, hydrogen, helium and other gasses expanding at a rate of around 220,000 kilometers (136,700 miles) per hour 

Sparkling at the centre of this beautiful NASA/ESA Hubble Space Telescope image is 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, and its uncatalogued stellar sidekick, 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 kilometres per hour! Unfortunately, the lifecycle of a Wolf–Rayet star is only a few hundred thousand years — the blink of an eye in cosmic terms. Despite beginning life with a mass at least 20 times that of the Sun, Wolf–Rayet stars typically lose half their mass in less than 100 000 years. And WR 31a is no exception to this case. It will, therefore, eventually end its life as a spectacular supernova, and the stellar material expelled from its explosion will later nourish a new generation of stars and planets.
Credit: NASA/ESA

Space news (March 11, 2016) – 30,000 light-years away in the constellation Carina (The Keel) – 

The Wolf-Rayet star WR 31a, near the centre of this Hubble image, is a bright celestial beacon ejecting hydrogen in layers that are interacting with extremely fast-moving stellar winds to produce the ring-shaped bubble of an interstellar cloud of dust, hydrogen, helium, and other gases viewed. 

Wolf-Rayet stars are the most massive stars detected during the human journey to the stars. WR 31a started life with over 20 times the mass of Sol. Our Sun is a main sequence star which is actually a little bigger than average. The more mass a star has, the shorter its expected life, which accounts for the short life span of this bright celestial beacon. In the words of NASA, massive stars “Live fast and die hard”. 

The mass of WR 31a puts it at the lower end of the mass scale for Wolf-Rayet stars, with the most massive estimates coming in at over 200 times the mass of our sun. The estimates of the mass of this type of star are still being worked on, so don’t take them to heart. 

Astronomers estimate WR 31a is only 20,000 years old, give or take a few thousand, which is around 10 percent of its life expectancy according to current theory. The life cycle of Wolf-Rayet stars is only a couple hundreds thousand years long, a mere blink of the eye in cosmic terms, which means this massive star will end its days as a spectacular supernova. 

The event we refer to as supernova is an essential part of the life cycle of the cosmos. Deep within these massive stars, the building blocks of the cosmos are created. It’s here the carbon, magnesium, calcium, and other elements that make up 4-5 percent of the universe are made using the extreme conditions that exist. 

We’re all stardust traveling on a pale-blue dot in the distance, across the vastness of space-time to an unknown but dreamed of ending. 

Watch this YouTube video on Wolf-Rayet star WR 31a.

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You can learn more about Wolf-Rayet stars here. Talk to an astronomer about it here.

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Learn more about the birth and death of stars here

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