European scientists using ESO’s Very Large Telescope (VLT) have learned what the weather is like on the surface of one of the objects in a binary system called Luhman 16AB.
Luhman 16AB, also known as WISE 1049-5319, is a pair of brown dwarfs located in the southern constellation of Vela, about 6 light-years away from Earth.
Discovered in 2013, it is the third closest system to the Sun, after Alpha Centauri and Barnard’s Star.
The fainter component of the system, Luhman 16B, had already been found to be changing slightly in brightness every few hours as it rotated – a clue that it might have marked surface features.
Now, the astronomers from Germany, France and the United Kingdom have used the VLT to map out clouds on its surface.
The cryogenic high-resolution infrared echelle spectrograph (CRIRES) on the telescope allowed the team to see the changing brightness as Luhman 16B rotated and whether dark and light features were moving away from, or towards the observer.
By combining all the results they could recreate a map of the dark and light patches of the surface.
“Previous observations suggested that brown dwarfs might have mottled surfaces, but now we can actually map them,” said Dr Ian Crossfield of Max Planck Institute for Astronomy in Heidelberg, who is the lead author on a paper published in Nature (full paper in .pdf).
“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,” he said.
I.J.M. Crossfield et al. 2014. A global cloud map of the nearest known brown dwarf. Nature 505, pp. 654–656; doi: 10.1038/nature12955