NASA’s Hubble and Spitzer telescopes have revealed interesting effects on the surface of a Brown Dwarf star that look like weather patterns.
Brown Dwarfs are something of a problem child when it comes to stellar objects – they’re much more massive than a planet (even planets like Jupiter) , but they’re not massive enough to sustain the nuclear fusion reaction that fuses Hydrogen nuclei into Helium as in main sequence stars.
As a result they tend to be a lot colder (relatively speaking – they’ll still be a good few hundred degrees C)and either a companion to a larger, active star or adrift in the void between other stars, shining so dimly that we cannot see them. You might remember in the film 2010: Odyssey Two (the sequel to 1999: A Space Odyssey) that Jupiter was crushed by the monoliths so that the process of nuclear fusion would start.
In the case of Brown Dwarfs, the gas cloud that they formed from didn’t have enough mass to achieve the required pressure or temperature to start fusion. So the core gets very hot – but not hot enough. In the case of this failed ignition a tell tale marker of lithium gets left behind as a star with active fusion would normally burn the lithium that remains.
But I digress.
Researchers using NASA’s Hubble and Spitzer telescopes apparently used a combination of techniques and came up with some very interesting results while observing a brown dwarf with a very easy to remember name – 2MASSJ22282889-431026.
The technique they used was one called photometry – very crudely its where you note the brightness of a stellar object over a set period of time. The key part of their technique is that the two telescopes used different wavelengths while observing the brown dwarf at the same time. Plotted on a graph sharing the same time index, the relative “brightness” for each wavelength was different.
This finding suggests that there are active weather systems – higher layers in the atmosphere filter out infrared wavelengths coming from the surface.
According to theorists involved in the research these weather patterns could be particularly Hellish. Adam Showman, at the University of Arizona said, “The data suggest regions on the brown dwarf where the weather is cloudy and rich in silicate vapor deep in the atmosphere coincide with balmier, drier conditions at higher altitudes — and vice versa,” while Mark Markley of the NASA Ames Research Center commented: “Unlike the water clouds of Earth or the ammonia clouds of Jupiter, clouds on brown dwarfs are composed of hot grains of sand, liquid drops of iron, and other exotic compounds.”
Over the coming months NASA plan to look at other brown dwarves to fine tune this technique before turning their sights onto Exoplanets, presumably in attempts to determine their precise atmospheric compositions.
Image: NASA/JPL Materials.