Scientists Use “Sunglasses” to See Bands of Clouds on a Brown Dwarf

Artist’s concept of Luhman 16A. The red object in the background is Luhman 16B, the partner brown dwarf to Luhman 16A. Together, this pair is the closest brown dwarf system to Earth at 6.5 light-years away. Credit: Caltech/R. Hurt (IPAC)

(News via Caltech)

Astronomers have detected what appear to be bands of clouds streaking across the surface of a cool star-like body known as a brown dwarf. The bands, resembling those that stripe the surface of Jupiter, were discovered using polarimetry, a technique that works in the same way that polarized sunglasses block out the glare of sunlight.

“I often think of polarimetric instruments as an astronomer’s polarized sunglasses,” says Maxwell Millar-Blanchaer, a Robert A. Millikan Postdoctoral Scholar in Astronomy at Caltech. “But instead of trying to block out that glare we’re trying to measure it.” Millar-Blanchaer is lead author of a new study on the findings, accepted for publication in The Astrophysical Journal. The observations were made using the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

The researchers explain that, although they cannot image the brown dwarf itself, their measurement of the amount of polarized light coming from it allows them to infer the presence of cloud bands through sophisticated atmospheric modeling. Their observations do not allow them to specify exactly how many bands of clouds are rotating around on Luhman 16A, but according to their models, the answer could be two.

Their models also show that the patches of clouds would have stormy weather similar to that on Jupiter.

“We think these storms can rain things like silicates or ammonia. It’s pretty awful weather, actually,” says co-author Julien Girard of the Space Telescope Science Institute.

In the future, the team hopes to extend this work to measurements of planets around other stars, called exoplanets.

Source/read more: Bands of Clouds Swirl Across Brown Dwarf’s Surface |