First weather map of brown dwarf

Jan 29, 2014
This artist's impression is based on the first ever map of the weather on the surface of the nearest brown dwarf to Earth. An international team has used ESO's Very Large Telescope to make a chart of the dark and light features on WISE J104915.57-531906.1B, which is informally known as Luhman 16B and is one of two recently discovered brown dwarfs forming a pair only six light-years from the Sun. Credit: ESO/I. Crossfield/N. Risinger

ESO's Very Large Telescope has been used to create the first ever map of the weather on the surface of the nearest brown dwarf to Earth. An international team has made a chart of the dark and light features on WISE J104915.57-531906.1B, which is informally known as Luhman 16B and is one of two recently discovered brown dwarfs forming a pair only six light-years from the Sun. The new results are being published in the 30 January 2014 issue of the journal Nature.

Brown dwarfs fill the gap between , such as Jupiter and Saturn, and faint cool stars. They do not contain enough mass to initiate nuclear fusion in their cores and can only glow feebly at infrared wavelengths of light. The first confirmed brown dwarf was only found twenty years ago and only a few hundred of these elusive objects are known.

The closest brown dwarfs to the Solar System form a pair called Luhman 16AB that lies just six light-years from Earth in the southern constellation of Vela (The Sail). This pair is the third closest system to the Earth, after Alpha Centauri and Barnard's Star, but it was only discovered in early 2013. The fainter component, 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 astronomers have used the power of ESO's Very Large Telescope (VLT) not just to image these brown dwarfs, but to map out dark and light features on the surface of Luhman 16B.

ESO's Very Large Telescope has been used to create the first ever map of the weather on the surface of the nearest brown dwarf to Earth. An international team has made a chart of the dark and light features on WISE J104915.57-531906.1B, which is informally known as Luhman 16B and is one of two recently discovered brown dwarfs forming a pair only six light-years from the Sun. The figure shows the object at six equally spaced times as it rotates once on its axis. Credit: ESO/I. Crossfield

Ian Crossfield (Max Planck Institute for Astronomy, Heidelberg, Germany), the lead author of the new paper, sums up the results: "Previous observations suggested that brown dwarfs might have mottled surfaces, but now we can actually map them. 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."

To map the surface the astronomers used a clever technique. They observed the brown dwarfs using the CRIRES instrument on the VLT. This allowed them not just to see the changing brightness as Luhman 16B rotated, but also to see whether dark and light features were moving away from, or towards the observer. By combining all this information they could recreate a map of the dark and light patches of the surface.

ESO's Very Large Telescope has been used to create the first ever map of the weather on the surface of the nearest brown dwarf to Earth. An international team has made a chart of the dark and light features on WISE J104915.57-531906.1B, which is informally known as Luhman 16B and is one of two recently discovered brown dwarfs forming a pair only six light-years from the Sun. The figure shows the object at sixteen equally-spaced times as it rotates once on its axis. Credit: ESO/I. Crossfield

The atmospheres of brown dwarfs are very similar to those of hot gas giant exoplanets, so by studying comparatively easy-to-observe astronomers can also learn more about the atmospheres of young, giant planets—many of which will be found in the near future with the new SPHERE instrument that will be installed on the VLT in 2014.

Crossfield ends on a personal note: "Our brown dwarf map helps bring us one step closer to the goal of understanding weather patterns in other solar systems. From an early age I was brought up to appreciate the beauty and utility of maps. It's exciting that we're starting to objects out beyond the Solar System!"

Explore further: Stormy stars? Spitzer probes weather on brown dwarfs

More information: This research was presented in a paper, "A Global Cloud Map of the Nearest Known Brown Dwarf", by Ian Crossfield et al. to appear in the journal Nature: dx.doi.org/10.1038/nature12955

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User comments : 6

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Osteta
Jan 30, 2014
This comment has been removed by a moderator.
Captain Stumpy
not rated yet Jan 30, 2014
@osteta Zephyr
The accepted model model of star formation predicts, that dwarf stars burn their fuel slowly

first off... they use fusion, they dont "burn" their fuel
and as for rate of fuel use, IIRC - it depends on the size/mass of the star
But no red dwarf consisting of hydrogen and helium only has been found so far.

based upon your statements:
you are making an assumption that we have found most of them in the universe

ALSO – given that the article is about Brown Dwarfs:
are you getting confused based upon this comment in the article?
Brown dwarfs fill the gap between giant gas planets, such as Jupiter and Saturn, and faint cool stars
[sic]
or are you changing the subject?
GSwift7
5 / 5 (2) Jan 30, 2014
Red dwarfs violate the Big Bang cosmology


First, the article is about brown dwarfs, which aren't stars, not red dwarfs.

Second, a very old red dwarf would have had time to convert a significant amount of itself into heavier elements by now. And newly formed red dwarf stars would be composed of a heavier mix of elements to begin with. Besides, isn't it possible that the first generation of stars in the Universe were almost all huge? Perhaps the majority of red dwarfs aren't first generation. Since most stars in general aren't first generation, I would assume that the same would be true of red dwarfs.

Edit: I see that the captain beat me to it, but I'll let my post stand anyway. Good job Captain.
Fleetfoot
5 / 5 (1) Jan 31, 2014
.. if born as first generation stars they should exist today without heavy elements in their composition.


True, but who said these were first generation?

Brown dwarfs are simply low mass stars and will still be forming today. In fact, since metals (from earlier supernovae) allow the gas to cool more efficiently, brown dwarfs are much more likely to form later. Pop I stars are expected to have been very massive because of that.
Osteta
Jan 31, 2014
This comment has been removed by a moderator.
baudrunner
not rated yet Feb 01, 2014
Forget about seeing this baby through the WorldWide Telescope. It's just too faint. It does kind of beg the question why they are ignoring http://www.worldw...35617876 ? WWT doesn't even have a label for it yet. You can only see that one in the infrared, especially the IRIS improved rendition. Not there in the visible range, but the most impressive of all the IR objects in WWT. What is it, anybody out there know, please?
baudrunner
not rated yet Feb 01, 2014
If you've downloaded WorldWide Telescope for personal use, you can locate http://www.worldw...35617876 using ra:09h 47m 59s dec:13 16' 27".
Fleetfoot
5 / 5 (2) Feb 04, 2014
Brown dwarfs are simply low mass stars and will still be forming today
But why they weren't formed in epoch of first generation of stars? After all, our Milky Way is 12 billions of years old, so it should be full of the brown dwarfs formed with hydrogen only. ...


Without metals, hydrogen and helium are vary poor at radiating. If you look at a pure hydrogen flame, or even natural gas, it can be hard even to see it. The bright yellow light from a candle on the other hand is due to the heating of soot grains by the flame. Because of that, low metallicity nebulae get much bigger and hotter before they can radiate enough heat to start forming a star. The earliest Pop III stars are expected to have masses around 100 times that of the Sun for this reason.