http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.4059v2.pdf

via :

http://arxiv.org/abs/1105.4059

via that first link posted in the Opening Post / article here.

This interesting clip :

http://www.space.com/9848-closest-star-wise-brown-dwarfs.html

via space-dot-com is somewhat more “plain english” and less technical but also now rather less up to date. Alas my preliminary search couldn’t find any news items there on this latest brown dwarf duo discovery.

So I take it they are, indeed, solitary borwn dwarfs each wanderuing the cosmos on its own. Of course, they may or may not boast exoplanets and cometary clouds or asteroid belts – so much still remains to be discovered and hopefully follow up studies will be done.

Which is somewhat unusual – given many of the nearby brown dwarfs do indeed appear to be companions tolarger stars – but isn’t unprecedented as othersolitary brown dwarfs are known.

Are these two new brown dwarfs actually *solitary* brown dwarfs, not part of a larger star system? Or are they merely orbiting the blue thingies shown in the pictures?

There are two different definitions for brown dwarfs: One defines a brown dwarf as an object that forms like a star but lacks the mass to sustain hydrogen fusion (but IS capable of limited hydrogen and deuterium fusion- it’s just that fusion never produces enough pressure to balance out gravitational contraction) The other definition basically leaves out the “forms like a star” part. Then there are other theories that say brown dwarfs form like brown dwarfs, and there’s some third mechanism…

Theorists prefer the first definition; many observationalists prefer to ignore how it formed and just figure out what it is. I once went to a WISE talk about a brown dwarf with spectral class colder than T10, which they believed might be 5 Jupiter Masses. That sounds like a free-floating planet, but by their theoretical definition it’s a brown dwarf because it’s not orbiting a star and may have formed on its own, and they don’t actually KNOW its mass anyway. (In the talk, the WISE people said they preferred the term “object”).

Ultimately, the problem is that all we know is the temperature, rotation, composition, and surface gravity of an object, which gives us very limited information about what’s going on at the core. Some of WISE’s brown dwarfs may actually be feeble stars, some of WISE’s red dwarfs may actually be massive brown dwarfs. We can speculate based on models of their interior physics, but there’s currently no known way of determining for certain if an object with a ~2000-degree upper atmosphere is a brown dwarf or a star.

EDIT: Actually, the way to determine it would be to luck upon a relatively old nearly-equal-mass binary system where one of the objects was genuinely a lot cooler and dimmer than the other one (no dust obscuration). In that case, we could get the masses of the (bright) star and (dim) brown dwarf and figure out where the mass limit was, for that particular composition, magnetic activity, and rotational velocity.

http://kencroswell.com/reddwarflife.html

by Ken Croswell observes that’s no longer the case for them. So perhaps some similiar rethinking regarding brown dwarfs isn’t beyond the realm of the concievable.

Croswell has also written interestingly on brown dwarfs here :

http://kencroswell.com/100BillionBrownDwarfs.html

& here :

http://kencroswell.com/BrownDwarfLithium.html

too which are perhaps worth reading in this context /thread.

Even though brown dwarfs do not have sufficient mass to fuse atoms like in a star from what I understand they do radiate both heat and light. I’ve always wondered if there is a goldilocks zone around these objects. If a small planet or moon was close enough to a brown dwarf would it receive sufficient heat and light to possibly harbor life. If this somehow proved to be the case it would open a lot of other possibilities in the search for life…. I love astronomy!

Me too!

Sadly, I think that a brown dwarf having a habitable planet is probably really stretching plausibilities given how very small and close in that limited space will be.

Someone who knows and is good at maths can no doubt calculate it but it may be that the habitable zone of a brown dwarf is actually inside the Roche limit where no planet or moon but only rings can exist. (click on my name for the wiki-basics of the Roche limit.)

Mind you, I could be mistaken and if there is more than just the one star in the system – say a brown dwarf orbiting another brighter star, who knows? A brown dwarf may not make for a habitable planet on its own but in combination – perhaps?

Which, as always when we find new nearby stars, make me wonder: are there faint, cool brown dwarfs even closer to us? Is it possible that Proxima Centauri, a red dwarf 4.2 light years away, is not the closest star to the Sun?

Shortly after WISE had been launched back in June 2009 I posted a poll asking that very question on the BAUT forum – click on my name to see via linkage.

I asked there & percentage~wise got :

***

1. WISE will find more than one brown dwarf or star closer than Proxima = 47.37%

2. WISE will discover a brown dwarf closer to us than Proxima Centauri = 36.84%

3. No, Proxima Centauri will keep its record & we won’t find anything nearer = 31.58%

4. WISE will find an iceberg cold or colder brown dwarf closer than Proxima = 15.79%

5. WISE will discover a red dwarf closer to us than Proxima Centauri = 5.26%

***

Looks like the verdict is still uncertain years later which I must admit I hadn’t imagined would happen at all!

Really looking forward to them finishing going through all the WISE data so we can say for sure one way or the other!