This is how 'lava planets' change over time
What's the story
A recent study published in Nature Astronomy has proposed a theoretical framework to understand the evolution of hot rocky exoplanets, or "lava planets." The research was led by Charles-Edouard Boukare, an Assistant Professor at York University. The study combines geophysical fluid mechanics, exoplanetary atmospheres, and mineralogy to explore how lava planet compositions evolve through a distillation-like process.
Exoplanetary characteristics
What are lava planets?
Lava planets are Earth- to super-Earth-sized worlds that orbit their host stars at extremely close distances, finishing an orbit in less than a single Earth day. They are tipped to be tidally locked like Earth's Moon, always showing the same face to their star. The dayside surfaces of these planets reach such high temperatures that silicate rocks melt and even vaporize, thus creating conditions unlike anything in our solar system.
Chemical processes
Study outlines their evolution
The unique orbital configuration of lava planets maintains vapor-liquid and solid-liquid equilibria over billions of years, thereby driving long-term chemical evolution. The study predicts two end-member evolutionary states: a fully molten interior for likely young planets and a mostly solid interior for likely older ones. In the latter, only a shallow lava ocean remains on the dayside while the atmosphere becomes depleted in elements such as sodium, potassium, and iron.
Future research
JWST observations will test the predictions
The study's predictions have earned 100 hours of observation time on the James Webb Space Telescope (JWST). These upcoming observations will test the theoretical framework proposed in this study. Boukare hopes these observations will help distinguish old lava planets from young ones, thus marking an important step toward moving beyond the traditional snapshot view of exoplanets.