Wolf-Rayet: The Day The Bubble Burst

It’s a story that began 20000 years ago, and has been waiting for you. Like something out of a “Star Trek” episode. The vista before you hangs in the black like a portal into the fiery underbelly of all that’s good in the Universe.

WR-124. Like a passage leading into the flaming maw of Hades itself.. Image: ESA/Hubble and NASA

“Star Trek” You remember it now. The Battle of Wolf-359. It was a classic episode, in which a tattered human military force took on a vastly superior foe: the Borg. These creatures were bloodless and implacable. Truly unsettling bad guys.
This monster is just as unsettling. Wolf-Rayet-124 is real. It’s huge. You’ve come a long way to encounter it. A small fleet of drone-sats has been dispatched to get up close and personal with this Wolf-Rayet star, to see how extreme extreme sports can get.

As soon as humans got comfortable in space and started calling all kinds of dark corners and odd rocks home they were up to their usual mischief. As soon as all the laws were decreed and the soapboxes were all put away, humans got back to the serious business of finding new and bizarre ways to enjoy themselves.

To Hell with that.

Space tourism didn’t become big business. It became exponentially big business. Extreme sports fans weren’t interested in scuba diving with great white sharks anymore, or parachuting.
Ha! You recall the stories. The One-G-ers were those quaint old extreme sportsters who couldn’t let go of old mother earth. Most of them were toothless and half nuts decades ago, but they still harped on about climbing Mount Everest or wrestling crocodiles.

You look upon Wolf-124, blazing with a luminosity several million times greater than Earths sun back home. Wolf-124 is huge. How huge? These kinds of stars are rare. Of the millions of stars known to humanity only around 500 Wolf-Rayet stars are known to exist in this galaxy.

Wolf-Rayet stars are thought to be the powerhouses driving many planetary nebula or stellar nurseries. How does this work?

Your little drone sats are tasting the cloud of ionised gas and interstellar gunk that swirls around the star. This cloud is nearly 6 light years across; a dusty miasma flung outwards by the intense solar winds radiating from the star within. From your vantage point out here, looking down into this slow maelstrom you see chunks of the star heading outward. Earth sized pieces of WR-124 soar through the cloud like the volcanic rage of a demon tearing itself apart.

You write that last line down. The tourists will love it.

Sometime around 20000 years ago, when human beings were first discovering Europe WR-124 began tearing itself apart. Scientists never really ascertained why, but it’s made for some great observations over the years. Tourists will love this. You got here first, to set up the first fleet of solar sailing yachts. The winds from the star crack along at 1600 km per second, fast enough to twist the most iron stomachs.

These stars have unusual emission spectra. Many of the space tourists won’t care what this is, but there’s always someone in every group who just has to understand what they’re leaping into. Fair enough. What it means is that like any other star a Wolf-Rayet star burns up fuel. Our star, a relatively youthful star somewhere near middle age, is still burning hydrogen via the process of stellar fusion. As a star ages it’s supply of hydrogen becomes depleted, and it must burn heavier elements in order to survive.Wolf-Rayet stars are often seen to have high levels of quite heavy elements or “metals” such as carbon or nitrogen in their upper atmosphere. This is due to nearly complete depletion of hydrogen fuel so as a result heavier elements are being used up.

What does this have to do with spectra?  Well, as elements transition from higher to lower energy states, ie when they’re being burned up inside a star, photons of particular wavelenghts are given off. It’s possible to tell just by analysing the wavelengths of light radiating from a star (it’s emmision spectra) what’s going on in and immediately around the star. This is why scientists know WR stars are old, and what they’re burning off in place of hydrogen. It’s also the reason they can infer the presence of extreme solar winds. The luminosity and heat given off by a WR star is extreme. At it’s surface a WR star can reach temperatures of between 30000 and 200000 Kelvin; hotter by far than most other stars. Such radiative pressure literally manifests as a “wind”, with the abilty to exert pressure on objects, such as solar sails!

Sailing the Big Empty. Image: Andrzej Mirecki

Most of the drone sats are keeping a safe distance from WR-124. This might just be an imaginary blog post, but you have imaginary operating costs, you know?

So you’ve staked your claim here. Now, all that’s left to do is wait for the money to fly in!

Still, you’re thinking of your next venture. There’s an exoplanet out there somewhere: HD 189733B where it rains glass! Now that sounds like fun…..

While you’re here, join me on the AstroBiological YouTube channel. I’m hard at work sprucing it up. What do you think of this intro sequence?

One last thing! 

Hop onto WeCreateEdu: an online community for educational you tubers. There is a galaxy of stuff to learn and explore here. Very much worth a look:

https://www.youtube.com/channel/UCaSBVqfz2RjL3lBC3DX4aSw
Small YouTube channels are feeling the squeeze from some draconian new measures by Google which effectively punish small creators and make it almost impossible to gain traction. Some thoughts on the matter from a fellow YouTuber. 

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