Thanks to a Bluesky post by the Space Telescope Science Institute, I found out about a ridiculously gorgeous JWST image of a nearby star that’s busily forming planets around it. Behold, IRAS 04302+2247! [link to journal paper]

I know, right? Click here to get a much larger 3,400 x 2,000 pixel version.

This spectacular object is a little over 500 light-years from Earth, and is part of a much larger complex of gas and dust in the constellation of Taurus, where lots of stars are forming. What you’re seeing—well, what you’re not seeing, to be truthful—is a very young star, called a protostar, probably less than a million years old. The protostar is surrounded by the material from which it formed, and we see that as the gorgeous wispy material to the left and right.

Closer in, the material gets brighter, and right at the center is that vertical dark line — that’s a dense disk of matter swirling around the protostar. It’s so thick, in fact, that it completely blocks all the light from the star forming in the middle, which is why I said you’re not seeing it. By happenstance we see this disk almost exactly edge-on, so it looks like a thick line.

This is a JWST image, which means what you’re seeing is infrared light. That kind of light is usually pretty good at making its way out of dust and gas (it’s why firefighters sometimes use IR goggles to see people in smoke-filled rooms), but in this case the disk is so dense not even infrared gets out, so it appears black.

That disk is what planets form from! So this protostar is not only still forming itself, but it’s making its family at the same time. Awwww.

Butterfly-shaped nebulae (nebula is Latin for “fog”) are common in these sorts of objects. The star can blow a thin wind of material in all directions, but in the equatorial plane it hits that disk and stops, so it can only flow away above and below the disk, creating the wings. For IRAS 04302+2247, the wings aren’t symmetric, which is interesting. The one on the left is fainter than the one on the right — note that the wings are not glowing on their own; they’re reflecting light from the protostar. There are a lot of reasons this asymmetry can happen. For example sometimes there is material near the star that can block the light, creating a shadow, so one wing appears dimmer than the other; however it’s not clear what’s happening here.

Detailed measurements of the disk itself and the material immediately around it indicate they aren’t symmetric either. The astronomers who took this image think this could be due to an odd structure in the disk. Instead of being completely flat, the very innermost part of it closest to the protostar might be tipped, which causes the lighting to change a little bit. The slanted inner part could be due to the disk not being lined up with the star’s powerful magnetic field; or the protostar might actually be a binary, two stars orbiting, and the orbital plane is tipped to the disk, torqueing it; or it could be due to a still-forming giant planet near the star that isn’t orbiting in the plane of the disk (maybe it got too close to another giant planet and got thrown off into an inclined orbit). At the moment the observations don’t distinguish between these or other possible causes.

Just remember, the sun and our solar system may have looked a lot like this some 4.6 billion years ago. When we study these objects, we are peering into a version of our past, and from it we learn about how we literally came to be.

As I’ve written about a zillion times, different atoms emit different kinds of light when they’re excited. Zap them with, say, ultraviolet light, and an electron jumps up the energy levels. When it drops back down, it emits photons at very specific wavelengths, depending on the atomic number of the element and the energy levels it jumps from and to. In astronomy, we use this to identify what different objects are made of, and the abundances of the elements in them.

Tom Fields, an amateur astronomer who writes spectroscopy software for amateurs, has created a pretty cool poster that shows this. It’s set up like the Periodic Table of Elements you see in every chemistry classroom, but instead of info on the element it shows the actual emission spectrum for that element. It would look great on a science classroom wall or any nerd’s office. The linked page above has details.

Disclaimer: I don’t make any money or anything like that from this; I just think it’s cool.

I have more info on this kind of spectrum in Crash Course Astronomy, and this is a reminder to myself that I should probably do a more detailed write up explaining how this works. I talk about spectra a lot — it’s the key to all astrophysics, really — and having a basic explainer would be handy (especially for hydrogen and oxygen, the most common ones I talk about). Sigh. I’ll put it on my to-do list, which is expanding so rapidly the end is redshifted. Which I could measure with emission line spectra like these.

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