The first ever map of the weather on the surface of the nearest brown dwarf to Earth has been created by targeting the European Southern Observatory’s Very Large Telescope (VLT) on the failed star, six light years from our solar system – that’s slightly more than half the distance to the bright star Procyon in Canis Major. The dark and light features on the recently discovered WISE J104915.57-531906.1B, also known as Luhman 16B, shows the turbulent weather patterns in this half of a binary brown dwarf pair.
Brown dwarfs fill the gap between giant gas planets, such as Jupiter and Saturn, and faint cool stars. They don’t contain enough mass to initiate nuclear fusion in their cores – required to become a fully fledged (or main sequence) star. But they do glow feebly at infrared wavelengths of light. This allows astronomers to use infrared to examine the clouds and storms that form on gas giant planets and brown dwarf stars far away from Earth.
The first confirmed brown dwarf was only found twenty years ago and only a few hundred of these elusive objects are known. But galaxies are suspected to be littered with these very low-mass stars, either as binary dwarf systems, feeble companions to main sequence stars or solitary drifting objects in orbit around the galactic centre.
This imaging technique gives adds further capabilities in the new field of exometeorology. Clouds and storms on gas giant planets and brown dwarfs can be watched and monitored in infrared, similar to how amateur astronomers using visible light can watch Jupiter’s clouds and storms evolve over time. In this case, however, the task is made far more difficult by being 100,000 times further away than Jupiter. And that’s why the might of the European Southern Observatory’s VLT in Paranal Chile is needed.