Anyone who has headed eagerly down to the beach only to arrive just in time for an expected downpour will know that, traditionally at least, forecasting weather isn’t easy. But recent work by astronomers in Chile using the Very Large Telescope (VLT) to observe small gas planets, provides such insight into their conditions that it may be possible to predict the weather light years away on extraterrestrial bodies — even if we can’t always get it right here.
The planets in question, known as brown dwarfs, fill the gap between gas giants, like Jupiter and Saturn, and faint cool stars. They produce little light as they lack the mass to initiate nuclear fusion and therefore only glow weakly at the infrared wavelength, making observation difficult.
Although the first brown dwarf was discovered only 20 years ago, hundreds are known today. Among those closest to us is Luhman 16B, discovered in early 2013.
Astronomers at the European Southern Observatory (ESO)-run VLT — located on Cerro Paranal in the Atacama Desert — have now imaged this planet and mapped out light and dark features that mark its surface.
The lead author of a research paper on the work, researcher Ian Crossfield from the Max Planck Institute for Astronomy, summed up the results.
“Previous observations suggested that brown dwarfs might have mottled surfaces, but now we can actually map them,” he explained. “Soon, we will be able to watch cloud patterns form, evolve, and dissipate on this brown dwarf — eventually, exometeorologists may be able to predict whether a visitor to Luhman 16B could expect clear or cloudy skies.”
Due to the atmospheric similarities between brown dwarfs and hot gas giant exoplanets, astronomers hope the study of planets such as Luhman 16B could help them learn more about their more difficult to observe cousins.
“Our brown dwarf map helps bring us one step closer to the goal of understanding weather patterns in other solar systems,” Crossfield said. “From an early age I was brought up to appreciate the beauty and utility of maps. It’s exciting that we’re starting to map objects out beyond the Solar System!”
Due to its almost non-existent humidity and clear skies, the Atacama is the world’s premier location for astronomy. Chile is home to almost half the world’s telescope infrastructure, and this is set to increase to over two thirds in the next decade.