There has been research that suggests that the changing brightness of Brown Dwarves are due to bands of Iron/Silicate clouds. Several models have been made that supports that hypothesis. My question is: Which part of the model are the actual clouds? Are the clouds the bright orange bits? Or are those bright areas “breaks” in the clouds and a view of the Brown Dwarf below.

Artist Rendition

5 MB animated GIF: Brown Dwarf Cloud Model

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    $\begingroup$ Please note that the animated image takes up 5 MB of bandwidth (a lot for many phone users and people not lucky enough to have high bandwidth internet connections) whereas the still image takes up a mere 36 KB and is plenty of illustration - if illustration is needed. $\endgroup$ Jun 24, 2019 at 11:27

1 Answer 1


Initial research proved to be wrong as intuition does not match up with expectations.

Anyway, the paper referenced by the OP seems to sum up the answer to the question pretty well:

In this explanation, the dark areas of our map represent thicker clouds that obscure deeper, hotter parts of the atmosphere and present a higher-altitude (and thus colder) emissive surface, whereas bright regions correspond to holes in the upper cloud layers that provide a view of the hotter, deeper interior.

Extract from A global cloud map of the nearest known brown dwarf

Initially I assumed that the metallic clouds would reflect radiation from the nearby star, however as it turns out the hot atmosphere is emitting infrared radiation which affects the brightness much more significantly.

More on Brown Dwarfs at here.

  • $\begingroup$ Other sources contradict yours which is why Im scratching my head. The below link found that the clouds decreased brightness in those regions. researchgate.net/publication/… $\endgroup$ Jun 24, 2019 at 12:05
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    $\begingroup$ I’ll mark this as the answer but with a note. The Brown Dwarfs we are capable of studying are alone. They do not orbit other Stars. This could skew our results because, as Hug pointed out, the Iron-Silicate clouds have a high reflectivity. It’s unknown whether the clouds would “glow” in a solar system where the Brown Dwarf orbits a star. $\endgroup$ Jun 26, 2019 at 10:12

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