Starts With A Bang podcast #113 – Weird stars
- The stars that glitter all across the night sky are mostly constant throughout time: with the same size, brightness, and temperature over even very long periods of time.
- Some stars are different, however, pulsing as their outer layers expand, cool, and fainten, and then by contracting, heating up, and brightening.
- This variation over time is one way that stars can be “weird,” but those weird, variable properties can help us understand how the Universe itself is behaving.
When it comes to stars, most of them, for most of their lives, behave in a very similar fashion to the Sun. In their cores, they undergo nuclear fusion, which provides energy and creates radiation, and that outward radiation pressure holds the star up, internally, against gravitational collapse. For most stars, this balance between the pressure from outward radiation and the inward force from gravitation is nearly perfect all throughout the star, leading to an equilibrium state.
But some stars aren’t in this kind of equilibrium at all. Instead, some internal process actually drives the star in a fashion that causes it to pulsate: overshooting equilibrium in both directions, as it alternatingly expands and cools, and then contracts and heat up in a cyclical fashion. These species of intrinsic variable stars, including Cepheids and RR Lyrae stars, are not only of profound importance when it comes to understanding stellar evolution, but for unlocking the secrets of the distant Universe.
How do we understand these stars today, where are the frontiers, and what do we hope to learn about them in the coming years and decades? Especially as we transition into the era of “big data” in astronomy, where we aren’t observing individual stars in detail but rather thousands upon thousands of similar stars all at once, the answers to these questions are rapidly changing. I’m so pleased to share the first episode of 2025 with you, featuring our guest, Ph.D. candidate Catherine Slaughter, who takes us through all this and more. It’s a fascinating look into stellar physics, with possible implications for our own Sun’s fate, that you won’t want to miss!
