Welp, after six and a half years and 800+ issues, I’m afraid I can’t avoid this any longer: I have decided to raise my rates for this newsletter. The subscription prices have been the same since I started the newsletter in 2018, and it’s time.

The good news is it’s not a big jump: a Premium subscription will be US$6/month and US$60/year (formerly $5/$50). I’ll note that this is less than the inflation rate—five bucks in 2018 is worth $6.30 now. So hey, this is still a bargain!

This new rate will go into effect on Wednesday, January 22, 2025 on or around noon Eastern US time.

If you are an existing paid subscriber (and thank you for being one!), you don’t have to do anything. When your current subscription period ends you’ll automatically be billed for the new price.

If you’re a free subscriber now, you’re in luck: you still have two days to lock in the lower price before the increase. To be clear, if you sign up before Wednesday noon it’ll still be US$5/month or US$50/year. The benefits of being a paid subscriber are 1) getting three issues of the newsletter every week (the free one on Monday and then issues on Tuesday and Thursday); 2) you can leave comments on articles; and 3) logged-in paid subscribers don’t see ads, which I sometimes run. And of course you also get the warm glow of knowing you’re helping me, y’know, eat.

HOW TO SIGN UP:

If you want to become a paid subscriber, you can simply go to

https://badastronomy.beehiiv.com/subscribe

and enter your email address; it will take you to the Premium subscription page where the steps are pretty standard.

And hey, I’m happy to have subscribers at any level, free or paid. I love astronomy, and I love writing about it. Being able to share my thoughts (whether astronomy-based or whatever else fills these issues) with all y’all is a joy, and I’m grateful to have an audience. So: thank you. I appreciate you being here.

So let’s get to some cool astronomy!

It’s a rare thing to see actual movement in cosmic objects. Even incredibly rapid motion on a human scale shrinks to invisibility when viewed from light-years away. 

WR 140 is a rare exception to this. About 5,400 light-years from us, it’s a binary star, two stars orbiting each other. But it’s no ordinary binary; both components are extremely massive and luminous stars. One of them is a Wolf-Rayet star, which are terrifyingly energetic stars, sometimes blasting out over a million times as much light as the Sun does (I have details on all this in an article about WR 140 I wrote for Scientific American in 2022).

The two stars of WR 140 are on a highly elliptical orbit, spending most of the time separated by a large distance. But when they approach each other once every 7.9 years, an amazing thing happens. They are each blowing off an intense wind of gas, like the solar wind but far, far more intense. At periastron, when the stars are closest, those two winds collide, slamming into each other nearly head-on at colossal speeds.

When that happens, an immense wave of material moves outward from the star, carrying with it newly formed grains of dust (carbon-rich material) that are swept outward along the wave front. If this happened only once, we’d see a thin shell from the star moving outward, but it happens every 8 years or so, so we see wave after wave marching outward in neatly formed rows.

That material is hot, and emits light in infrared wavelengths, which is just where JWST sees best. Its keen vision allows it to separate out those rows of material… but there’s more. It’s observed WR 140 twice, once in 2022 and again a little over a year later. In the time between, those waves have moved outwards, and that motion was seen by JWST: 

LOOK. AT. THAT! [Click it to greatly embiggen]

The image on the left shows WR 104 in July 2022. The two stars are so close together that on this scale they look like one object. But you can see the ripples, the waves of material, each sent out every 7.9 years. The second image shows the same scene in September 2023. You can’t tell by eye, but those waves have moved: the third image shows a close-up where you can see the motion over that time.

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That’s phenomenal. Those waves are moving outward at 2,700 kilometers per second. That’s over 9 million kph. 16 separate events can be seen in the original images, each laden with carbon dust.

You can see that motion in this video:

The astronomers who did this research [link to journal paper] found the waves are clumpy on the small scale, and have determined that these clumps are important in the manufacture of that dust. Somehow those clumps act as factories for making dust grains, even in that ridiculously hostile environment.

[Incidentally, to get this view of the arcs, especially so close in to the source, the astronomers had to minimize the glaring interference from the bright stars, including those irritating diffraction spikes you see in all the JWST images that radiate outwards from the center. I have an article describing a similar situation to look at quasars with JWST. I used to do this same thing for Hubble images, and it’s tough to do, and I’m impressed with how well it worked here.]

If you look at wide-scale images of our galaxy, you’ll see dust lanes and filigrees and clouds strewn throughout, and that dust is an important factor in forming new stars. Much of that dust is created by the winds of massive stars as they die (like Betelgeuse does), but system like WR 104 play some amount of a role as well. That carbon is the the same carbon that all life on Earth is based on!

Wolf-Rayet stars are pretty incredible, and worth studying in their own right, but when we do, we’re studying in a small way how we ourselves came to be.

You can email me at [email protected] (though replies can take a while), and all my social media outlets are gathered together at about.me. Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or nine, too. Thanks!