Brown Dwarf Companion to Epsilon Indi

silent lurker writes "A team of European astronomers has discovered a Brown Dwarf object (a 'failed' star) less than 12 light-years from the Sun. It is the nearest yet known. Now designated Epsilon Indi B, it is a companion to a well-known bright star in the southern sky, Epsilon Indi (now "Epsilon Indi A"), previously thought to be single. The binary system is one of the twenty nearest stellar systems to the Sun. ...and astronomers believe there might be as many as 12x as many brown dwarf stars as there are visible ones! Hmmmm... Lots o' juicy fodder for SF content creators, dontcha think? ...not to mention astronomers themselves. See press release from European Southern Observatory. Another item is from Science Daily."

I've been there and I didnt see one.

[brejc8]

Well in Elite [frontier.co.uk] anyway.
Ah well... Lonely life.

Astrophysics 101

[barakn]

Some back-of-the-envelope calculations using some crude rules-of-thumb: Stars roughly follow a mass-luminosity relationship. L / Lsun=(M / Msun)^2.3 (for M.5*Msun). An estimate for this object indicates it should be .0007 times as luminous as the sun. Actually, due to the lack of fusion, it is only .00002 times as bright. Also, from Wien's displacement law (lamda_max*T = .290 cm K) and the object's estimated surface temperature of 1273 K, it's peak radiation occurs at a wavelength of 2280 nm, far into the infrared. The bulk of what little light brown dwarves emit is emitted in the infrared, making them practically invisible without a very expensive (and new) telescope. This has led to speculation that an unnoticed brown dwarf (the infamous Nemesis) could be orbiting our own sun!

Re:Astrophysics 101

[CanSpice]

The bulk of what little light brown dwarves emit is emitted in the infrared, making them practically invisible without a very expensive (and new) telescope.

Really? Then how is it that a 23-year old, 3.8 metre telescope [hawaii.edu] (which is cheap and old and small by today's standards) is able to not only detect brown dwarfs, but determine what kind of weather patterns their atmospheres have [hawaii.edu]?

Re:Astrophysics 101

[barakn]

UKIRT has had a series of upgrades starting in about 1990, including several generations of IR imagers, the addition of active optics, etc.. Thus the modern version of UKIRT is not 23 years old. Nor is 23 years particularly old compared to the ~400 years that telescopic observations have been made. If you read the fine print, you'll note that it took collaborative observations by 5 different telescopes to merely confirm that brown dwarfs vary in brightness (differently at different colors). While it might confirm they have weather, it certainly does not "determine what kind of weather patterns their atmospheres have." A confirmed observation of a brown dwarf was not made until 1995 (reference [hubblesite.org]).

Re:Lots of brown dwarfs?

[UrGeek]

If this discovery means there are 12 times the stars that we previously thought, does that not increase the chance of finding earth-like planets? Yes, given the brown dwarfs don't give out as much heat, but there is life on earth right now that does not depend on the sun - at geothermal vents, living via chemosynthesis. A frozen earthlike planet given the right amount of tidal energy (like Europa) or maybe internally generated heat could have life living under the ice.

And then maybe a planet very close to the brown dwarf would not be so frozen. There are scenarios that no one have thought of yet.

This can ONLY increase the change of finding more earth-like planets, if even only a bit.

12 times 100 billion is 1.2 trillion - and that is just in this galaxy.

Re:Lots of brown dwarfs?

[barakn]

Jupiter and Saturn could be considered brown dwarfs. They might actually prove to be crucial for the formation of terrestrial planets.

Re:Lots of brown dwarfs?

[CanSpice]

Actually, Jupiter and Saturn are too small to be considered brown dwarfs. The upper mass limit for brown dwarf is about 0.08 solar masses, or about 80 Jupiter masses. The lower limit is a little squishy, but most astronomers who study brown dwarfs would not include Jupiter in the brown dwarf category. The lower limit is probably something like 10 Jupiter masses.

Re:Lots of brown dwarfs?

[barakn]

7% of the exoplanets listed at this table [exoplanets.org] are greater than 10 Jupiter masses. Deuterium burning occurs at 10-12 Jupiter masses and greater, but doesn't help us categorize objects that have burned up their deuterium. 2-3 Jupiter masses might be a good dividing line, as it marks the transition from the object's radius increasing with mass to the radius actually decreasing with mass (which I won't go into as it leads to discussions of things like electron degeneracy pressure). Other definitions of planets and brown dwarfs make a distinction between the method of formation of the object, but this makes the mass much less important than the object's history, which is much harder to deduce. For instance, Jupiter was long regarded as having formed from runaway accretion starting with a small rocky core, but recent computer models [space.com] suggest it (and the other gas giants) formed directly from gravitational collapse, just like a star. Also consider the 55-78 Jupiter mass object [space.com] found orbiting at a distance roughly equivalent to Saturn's orbit around a sun-like star, a distance much too close for many astronomers' comfort.

Re:Lots of brown dwarfs?

[barawn]

Planets that have burned up their deuterium still have 10-12 times Jupiter mass - it's just that some percentage of it is deuterium. I really don't see what's wrong with the current brown dwarf definition of an object which can complete, has completed, or would be able to complete a portion of the pp chain at its core, but not all of it. This will give a cutoff of about 10-12 M_j, as you said.

The problem with the cutoff of how mass affects radius is that it's dependent upon a lot of other things besides mass (composition, and nuclear activity), whereas when you're in the 10-12 M_j range, regardless of what is actually at the core, you're probably going to be able to fuse deuterium. Again, it's an arbitrary fuzzy dividing line, but considering you're in the range of talking about "stars", which are all about nuclear fusion ("brown dwarf": portions of the pp chain only, "normal dwarf" - pp chain, "giant" - triple alpha chain) it's better to use a definition based on nuclear fusion to define it.

Actually might make more sense to add an additional distinction in the 2-3 M_j range too: gas supergiants. So gas giants = objects primarily composed of gases and 2-3 M_j but unable to sustain any nuclear fusion in their core, and brown dwarfs = objects > 10-12 M_j but unable to complete the pp chain.

Gas Supergiants

[barakn]

A stellar idea.

Re:Lots of brown dwarfs?

[iggymanz]

This just in, Dr. Mortimer Snerd of Bigscope Observatory has found an earthlike planet orbiting a brown dwarf 20 lightyears from earth. Says Snerd, "The planet is identical to earth in mass, orbital period, rotation, land to sea ratio, and elemental composition. It's just $&%*$# colder than a witches tit!"

Re:Lots of brown dwarfs?

[zer0vector]

I know the previous post was a joke, but I wanted to point out a flaw in logic. If it is identical to earth in mass and orbital period, than the mass of the "brown dwarf" would have to be the mass of the sun. So therefore it wouldn't be a brown dwarf at all, but rather a star.

Re:Lots of brown dwarfs?

[iggymanz]

actually no, if G the gravitational constant, M the sum of the mass of earth & "Snerd's Turd [he just named the brown dwarf], w is 2*pi over orbital period, and r the distance between "Witch-tit World" and Snerd's Turd, we find that:

G*M = w^2 * r^3

which shows that if we decrease M, it can be compensated for to yield same orbital period by decreasing the distance between the two bodies.

Dr. Snerd says he is folding a wire coathanger and to please report to the Observatory for your knuckle pimp-sticking

Need a better name!

[MonTemplar]

from the article :

• 
  Brown dwarfs are thought to form in much the same way as stars, by the gravitational collapse of clumps of cold gas and dust in dense molecular clouds. However, for reasons not yet entirely clear, some clumps end up with masses less than about 7.5% of that of our Sun, or 75 times the mass of planet Jupiter. Below that boundary, there is not enough pressure in the core to initiate nuclear hydrogen fusion, the long-lasting and stable source of power for ordinary stars like the Sun. Except for a brief early phase where some deuterium is burned, these low-mass objects simply continue to cool and fade slowly away while releasing the heat left-over from their birth.
  

Troll Stars, anyone? :)

Re:Need a better name!

[Alcohol Fueled]

"while releasing the heat left-over from their birth."

Would that be the equivalent of a star farting?

Re:Need a better name!

[Jupiter9]

A team of European astronomers has discovered a Brown Dwarf object (a 'failed' star)....

I thought they should name it Mandrakesoft [slashdot.org]

How much more....

[orthogonal]

So how much more dark matter must we account for to get the right Omega [queensu.ca] value?

You incensitive clods!

[GuyMannDude]

Brown dwarf? Good god! For those of you living in a cave, the proper ethnically-sensitive term is "Vertically-challenged African-American". How would you like someone to refer to you as "Whitey 4-eyes"? At least you guys had the sense to use the word "companion" rather than "hooker" although "escort" would also be acceptable.

Just because they don't spend their nights recompiling their Linux kernals doesn't make them any less of a person than you. Let's try to use modern terminology here, people!

GMD

Ask the Tellurites...

[ConceptJunkie]

IIRC, the Tellurites (big shaggy piggy folks) on Star Trek: TOS were from Epsilon Indi (or is it Indii).

I'd verify all this, but most of my Star Trek nerdophernalia is packed in a box somewhere.

Re:Ask the Tellurites...

[Anonymous Coward]

most of my Star Trek nerdophernalia is packed in a box somewhere.

Excellent. Identifying and isolating the problem are important first steps. Next is setting it on fire.

Good luck. And God's speed.

Re:Ask the Tellurites...

[ConceptJunkie]

Excellent. Identifying and isolating the problem are important first steps. Next is setting it on fire.

+1 Funny

I wish you could mod _up_ replies to your posts.

This just in!

[docbrown42]

"It was a big mistake" said one scientist "Apparently, someone had spilled chocolate pudding on the lens of the telescope, and suddenly you have everyone claiming to see 'brown dwarves.'"

Who spilled the pudding onto the lens was not immediately evident.

Too easy...

[Wireless Joe]

"A team of European astronomers has discovered a Brown Dwarf object (a 'failed' star)..."

Must...not...make...Gary Coleman...or Emmanuel Lewis...joke...too...late...

Sir, your slander is unnecessary.

[Kibo]

I object to the characterization of the star as "failed". While it may be true that it is something of an under-achiever, I would submit that Epsilon Indi B will eventually turn around and realize it's full potential.

If it could only find a one-by-four-by-nine monolith, Epsilon Indi B might well transform itself brilliantly. While Epsilon Indi B may live in a vacuum, its fate is far from predetermined, and who are you or anyone else to say otherwise?

Brown Dwarf?

[Bob Vila's Hammer]

Orbiting Uranus? Ass-teroid? In S.R. the dwarf browns you. There.