An exoplanet has to be very hot for rock to vaporize, as these brown dwarfs are, but not all brown dwarfs are in the right temperature range for this phenomenon to occur. Some are too hot, which causes the clouds to vaporize completely, while others are too cold, and the silicates either sink through the atmosphere or condense and fall to the surface as rain.
This research doesn’t only apply to brown dwarfs though. It is possible that silicate clouds could also form in our solar system on Jupiter, where the temperatures of the atmosphere are higher at the bottom of the atmosphere than at the top. This occurs because of the pressure created by the atmosphere, which pushes down on the lower atmosphere layers and heats them up. There could be silicate clouds hiding in the lower layers of Jupiter’s atmosphere that we can’t see because of the upper atmosphere.
The research helps refine our overall understanding of exoplanet atmospheres as well, which is important for not only studying distant worlds but also understanding our own planet, according to co-author Stanimir Metchev, also of Western University: “Understanding the atmospheres of brown dwarfs and planets where silicate clouds can form can also help us understand what we would see in the atmosphere of a planet that’s closer in size and temperature to Earth.”