The cluster Terzan 5 has many older, lower-mass stars present within (faint, and in red), but also hotter, younger, higher-mass stars, some of which will generate iron and even heavier elements. Image credit: NASA / ESA / Hubble / F. Ferraro.

Ask Ethan: Can Normal Stars Make Elements Heavier (And Less Stable) Than Iron?

It isn’t just supernovae or neutron star collisions that make the heaviest elements. The physics might surprise you!

“Comrades, this man has a nice smile, but he’s got iron teeth.”
-Andrei A. Gromyko

There are some 90+ elements of the periodic table that occur naturally in the Universe, but of them all, iron is the most stable. If you fuse lighter elements together to get closer to iron, you gain energy; the same is true if you split heavier elements apart. Iron represents the most stable configuration of protons and neutrons, combined, of any atomic nucleus yet discovered. At only element 26, however, it represents the end-of-the-line for most fusion reactions in even the most massive stars. Or does it? That’s what James Beall wants to know:

Iron has been called stuff like solar fusion ash that collects inside stars, as the last of the elements that fuse w/o consuming more energy than the fusion creates. I have read about the r-process and others that lead to heavier elements in novas and supernovas. My Q is if any elements heavier than iron fuse anyway in normal stars, even if it does consume more energy then it generates.