It could be argued that Earth hasn’t been an ideal place to live lately, but it could be worse. Scientists from Canada’s McGill University have released a new analysis of an exoplanet called K2-141b. This world orbits its star so closely that its ecosystem is deeply infernal. The soil is rock, the seas are rock and yes, the air is rock too.
Astronomers first detected K2-141b several years ago – it has the distinction of being the first planet identified during the Kepler Space Telescope’s “second light” mission, often called K2. It’s a few hundred light-years away, making it an impractical vacation spot. Not that you still want to go with a 100% chance that flaming rock storms will ruin all your outdoor activities.
K2-141b is such a hellish landscape because it is dense, rocky, and orbits incredibly close to its star. The planet has a density close to that of the Earth, so we have reasonably good models to estimate its conditions. Like most planets in close orbit, K2-141b is firmly locked to the star. This means that one side is roasted during an eternal day while the other is stuck in the permanent night. This dynamic is what makes K2-141b so inhospitable: if it rotated, things wouldn’t be so deadly.
By day, temperatures on K2-141b can reach 5,400 degrees Fahrenheit (2,982 degrees Celsius). It is hot enough to melt the rock, creating seas of lava that cover most of the surface to a depth of tens of miles. His also hot enough to fully vaporize the rock to create a subtle, sizzling atmosphere. On the far side of K2-141b, temperatures are around -328 degrees Fahrenheit (-200 degrees Celsius), which is substantially below the rock’s melting point. Then, as the vaporized rock atmosphere spreads to that side, it falls back to the ground. Earth has a water cycle, but K2-141b has a rock cycle. It is fascinating! But also incredibly hostile to life as we know it.
We don’t know the exact composition of the K2-141b, so the team had to create some models to describe a world of rock rain. For example, if the atmosphere is mainly silica or silicon monoxide, the “rain” would be molten rock, like a never ending volcanic eruption. If the crust is rich in sodium, the rain would pour into molten oceans like glaciers on Earth.
Of course, this is all a plausible hypothesis based on our limited data on K2-141b. We may find out how close this is to reality in the coming years. Scientists believe the next James Webb Space Telescope will be able to scan the atmospheres of some exoplanets such as K2-141b. NASA hopes to take this telescope into space in 2021.