back to article Room-temperature brown dwarf spied just 9 light-years off

Scientists perusing data collected by NASA's Wide-field Infrared Survey Explorer (WISE) have spotted some really cool stars – brown dwarfs with an atmospheric temperature as low as an agreeable 25°C. Dubbed "Y dwarfs", these objects have hitherto eluded astronomers hunting them at visible wavelengths, although WISE has finally …

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  1. Loyal Commenter Silver badge
    Boffin

    Can anyone enlighten me?

    What is it that distinguishes a brown dwarf from a large gas-giant planet?

    1. Adam-the-Kiwi
      Mushroom

      Re: Can anyone enlighten me?

      I think there's some debate over whether or not there is a continuum with stars at one end and gas giants at the other. The key definition of a star, though, is presumably that it has sustained fusion in its core at some stage. Deuterium fusion (D +p -> 3He + gamma) requires objects of around 15 Jovian masses, IIRC.

    2. David Hicks
      Boffin

      Not a lot

      A Brown Dwarf is basically a gas giant large enough that fusion can be sustained at the centre, though it's not really a star either on account of being quite dark and distinctly tepid.

      IIRC.

    3. Ru
      Boffin

      Easy.

      Giants are a lot smaller than Dwarfs.

    4. Martin Penny
      Boffin

      Re: Can anyone enlighten me?

      Size, and whether or not hydrogen fusion occurs within it.

      Taking some figures from our favourite on-line encyclopaedia, a stellar body needs to have a mass of approximately 8% of that of our Sun for the core pressure and temperature to get high enough for gravity-induced hydrogen fusion to occur; this also tends to "burn" lithium as well.

      However, the mass of a sub-stellar body may yet be high enough for other forms of fusion to occur, using "heavy" isotopes of hydrogen - primarily deuterium (hydrogen-2) - and also possibly "burning" lithium, usually when the it is younger and hotter (from gravitation condensation/contraction).

      If anyone can correct any mistakes I've made, please do so! :)

    5. Anonymous Coward
      Facepalm

      Might have something to do with....

      Don't planets need a star to orbit to be classed as a planet!

      1. fritsd
        Alien

        homeless planets

        @ cynical git: apparently not all of them, some are homeless!

        http://news.sciencemag.org/sciencenow/2011/05/homeless-planets-may-be-common.html?ref=hp

      2. rh587 Bronze badge

        Not just proximity to a star or...

        ...what would that make a Brown-Dwarf binary system them? Two planety yet starry things orbiting one another...?

    6. Danny 14 Silver badge
      Boffin

      yup

      mainly based on mass.

    7. Ragarath
      Mushroom

      I was

      Thinking the exact same thing when I read this. So I did some research (not a lot I admit)

      http://atramateria.com/the-coolest-neither-planet-nor-star-brown-dwarf/

      and

      http://en.wikipedia.org/wiki/Brown_dwarf#Distinguishing_low-mass_brown_dwarfs_from_high-mass_planets

      Should help explain a bit.

      Explosion: because brown dwarfs would like to start a reaction.

    8. Tomato42 Silver badge
      Boffin

      difference

      I'd say that it's either mass or the fact it doesn't orbit other celestial body in close proximity (as all stars orbit galactic center).

      The difference is as significant as the stuff that makes Pluto an ex-planet.

      1. Naughtyhorse

        doesn't orbit other celestial body in close proximity

        <cough>Binaries<cough>

    9. peterte
      Alien

      Fiat Lux!

      The classification originates from those smarty pants at Harvard:

      http://en.wikipedia.org/wiki/Stellar_classification

      It's been extended over the years and, like many classification schemes in astronomy (in my experience), it's a living thing as more objects are discovered that don't quite fit.

      http://en.wikipedia.org/wiki/Brown_dwarf

      Covers your very question - it suggests (although no reference given) that an object must have sustained fusion at some point to be counted as a star - seems reasonable.

  2. Anonymous Coward
    Anonymous Coward

    That brings up the question

    what's the surface gravity of those things?

    1. Evil Auditor Silver badge

      Surface?

      It's gas all the way down.

      1. Armando 123

        Um

        It either gets dense enough to form a liquid/solid core like Jupiter or gets so hot it's plasma. So no.

  3. Anonymous Coward
    Anonymous Coward

    Pointless picture?

    "NASA explains the purple hue shown in its artist's impression of a Y dwarf was chosen mainly for artistic reasons".

    In other words, here is a picture illustrating something that noone knows what it looks like.

    Oh, hum, wait, what?

    If people are rewarded according to their imagination, the guy in charge of the budget is on a 7 figures salary.

    1. Anonymous Coward
      Meh

      True true

      Based on that way of thinking never again should a dinasour be depicted as noone knows what colour they were.

      1. Anonymous Coward
        Joke

        What about

        Dinasweets?

      2. Anonymous Coward
        Anonymous Coward

        RE: true true

        Sorry to hear that you need the help of a NASA artist to grab the concept of a star being a sphere. If it helps, you can create your own explanatory star picture by choosing the "circle" tool from Paintbrush.

        In addition to shape, the point of dinosaurs illustration is to convey a sense of scale, which this pictures also fails to convey.

        1. Spoonsinger

          Re:- sense of scale (Cricri - wayback when).

          . <----- Uranus

          .

          .

          .

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    2. Andus McCoatover
      Windows

      Purple hue?

      Obvious.

      If it'd been coloured as a "Brown Dwarf", people would've mistaken it for a turd.

  4. cookieMonster
    WTF?

    Near...

    "Finding brown dwarfs near our sun is like discovering there's a....."

    For very extremely large values of "Near"...

    1. Yag
      Trollface

      very extremely large values of "Near"...

      ...are still ok for a mind-bogging ludicrously large universe :)

    2. Ralthor
      Thumb Up

      Titties? We dont neeed no stinkin' titties!

      In space terms 9 light years is next door. Just because you dont own a car doesnt mean the next town over isnt relatively close.

      For large values of close.

    3. Phil Standen
      Paris Hilton

      Re: Near

      I dunno....

      A pencil 3 desks away is not near.

      A cinema 1 street away is near, despite it being further away than the pencil.

      1. proto-robbie
        Coffee/keyboard

        y.a.f.t.

        Please see Ru @ 13:29 for the definitive explanation of this phenomenon. A work of genius.

      2. Blain Hamon
        Pint

        Obligatory quote

        Space is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.

  5. Anonymous Coward
    FAIL

    Really?

    "With WISE, we may even find a brown dwarf closer to us than our closest known star."

    Since our "closest known star" is the one we are in orbit around, I seriously doubt the accuracy of this statement....!

    1. laird cummings

      There's one in my back pocket.

      Can't have it though - go find your own.

    2. Anonymous Coward
      Anonymous Coward

      Sumerians already spotted it...

      ... And named it Nibiru!

  6. George Kapotto
    Joke

    Point of order...

    Finding a brown dwarf closer than our closest star would be quite a coup considering the closest known star is only 1 AU away from us. One would think that an even closer brown dwarf would have already been detected as a consequence of its gravitational influence. (Such as hurling the Earth out if its nice stable orbit into the deep cold of interstellar space.)

  7. Bassey

    Huh?

    "With WISE, we may even find a brown dwarf closer to us than our closest known star"

    What, closer than the Sun?

    1. asdf Silver badge
      Holmes

      great minds

      And petty people all think alike look at the three posts all together pointing out the obvious.

    2. proto-robbie
      Holmes

      You get a better class...

      of pedant here at the Reg.

  8. Nigel 11

    Last refuge of life?

    Interesting to note that such a "failed star" might become the last refuge of life in a dying universe, tens or hundreds of billions of years from now. Like the sun, they stay warm by nuclear fusion, but at such a low rate that they'll probably be the last places left where liquid water (and therefore life as we know it) can exist.

  9. Anonymous Coward
    Boffin

    they changed it !

    Thats just mean - the categories used to be Wow Oh Be A Fine Girl Kiss Me Right Now Sweetie

    (hmm, maybe the best way to find these things is to "look out the corner of your eye").

    brown dwarf star => nuclear reactions started upon gravitational collapse but then ran out of oomph

    gas giant planet => not big enough for collapse to initiate nuclear reactions

    e.g. jupiter ~ 1 order of magnitude too small to be any kind of star

    1. Ian Yates

      Mnemonic

      Only Big And Famous Guys Know More Love Than You?

    2. TimeMaster T
      Thumb Up

      Fish sticks and custard

      (hmm, maybe the best way to find these things is to "look out the corner of your eye").

      Nice!

      1. Anonymous Coward
        Anonymous Coward

        Re: Fish sticks and custard

        Are you a gay fish? With a custard/gunge fetish?

    3. Daniel Evans

      Or as my lecturers would say...

      Oh Bugger, A Fucking Goat Kicked Me

    4. Grumpy Old Fart

      as we know it?

      I find it incredibly hard to believe that life will be anything like it is now by the point we're approaching the heat death of the universe. In just 3.5 billion years we've gone from a single anaerobic bacteria to the duck-billed platypus*, discarding countless other forms, and possibly many different basic biochemistries, along the way, and we're not even halfway through the life of this single planet.

      * platypus = obviously the most complex form of life on the planet. Unnecessarily complex.

      1. Nigel 11

        Water ...

        We don't know much about what was on the surface of the earth before large parts of it got covered with liquid water, but there's no evidence that life can exist without water.

        All terrestrial life still extant shares a common basic biochemistry, with features such as RNA coding for proteins built from a common set of amino-acids, ATP energy-transport, lipid membranes, and an aqueous support medium. There must have been simpler life-systems leading up to this system (think scaffolding), but we have no evidence of what it might have been. I think it extremely unlikely that whatever it was, it did not require liquid water to function. Water is a lowest-common-requirement for all the more complex subsystems.

        I'm guessing that complex organisms find it hard or impossible to evolve in the atmospheres of gas giants or cool brown dwarfs. So they might remain at the single-celled stage "forever" until the brown dwarf no longer provides liquid water. Or until some exceptionally unlikely event happens, and multicellular or even intelligent life arises in the dark cold tail-end of a dying universe.

        BTW if you envisage galaxies as having been "mined-out" by interstellar-scale intelligences, then think of a brown dwarf ejected from its galaxy and drifting forever alone and undetectable through one of the voids in intergalactic space. That would, in fact, be a more stable environment than one stil in a chaotic orbit around the centre of a galaxy.

        The most complex form of life on the planet is surely some sort of insect. Butterfly: Egg, caterpillar, chrysalis ... complete dissolution of the caterpillar to a sort of living soup, and re-birth as a butterfly. Or spider-hunting solitary wasp. Somewhere in the egg is a program which allows it to hunt and paralyze spiders without becoming prey, dig a burrow, install the spider, lay an egg. I wish someone could tell me where and how.

    5. Blue eyed boy
      Unhappy

      When I were a lad

      and in my own experience, the S stood for Smack

    6. Nigel 11

      Jupiter is a very dark brown dwarf

      Jupiter emits more radiation than it recieves from the sun. Fusion at a very low rate is the probable source of the excess heat. Jupiter's core is believed to be mostly hydrogen in its theoretically predicted high-pressure metallic form.

      The Earth also emits more heat than it receives. In this case we have good reason to believe that the sources are radioactivity and tidal friction, and possibly also ongoing crystallisation of the Earth's solid inner core from its liquid outer core.

      For the Earth, the excees heat may have been the difference between a living planet and a snowball, in the early days when the sun was somewhat cooler and the moon was a lot closer.

  10. Vladimir Plouzhnikov

    Colour

    I believe the NASA's artist should know very well what visible colour will Y-Dwarf be @25C surface temperature - black.

    As to the colour of reflected light if someone will shine a flashlight on it - that's a different matter.

  11. Anonymous Coward
    Anonymous Coward

    Room-temperature brown dwarf

    that's not enough fibre, that is

    1. Anonymous Coward
      Anonymous Coward

      whereas

      a gas giant clearly has quantities of Ruby Murray in its immediate prehistory. They are often differently hued and, it goes without saying, they are often substantially above room temperature.

  12. Full Mental Jacket

    Missing mass

    Is it possible that the "missing mass" in the universe could also be room temperature or lower and hence not previously visible? (I've always suspected something like this)

    1. asdf Silver badge
      Boffin

      isnt?

      Most of the missing mass actually vacuum energy of space itself? Virtual particles are particles too.

    2. Armando 123

      Same here

      I studied astrophysics in grad school back in the early 90s and one day asked this. I said that, given that most of the light is in O and B stars, but the M stars, though individually small, are so much more numerous that they contain most of the mass, couldn't small M dwarfs, neutron stars, cooled white dwarfs, and brown dwarfs account for some significant portion of the "missing mass"? I was scoffed for thinking like a stellar astronomer.

    3. slevy
      Thumb Up

      MACHOs! and, BBN.

      Could much mass be in lumps of cool matter (dark rocky basketballs)? Nice question - was asked just this on an astrophysics test years ago.

      One kind of test made since: looking for "MACHO"s, massive compact halo objects. If much of our galaxy's missing mass were in brown-dwarf or other planet-to-star-sized lumps, they'd be detectable by gravitational lensing when one passed between us and a distant star. MACHO searches stared at huge fields of stars for the right kind of variability - brightening then fading over a day or so, with characteristic wavelength-independence that grav. lensing would do. Some have turned up, but not enough to be a large fraction of our Milky Way's gravitating matter. (But, lensing searches wouldn't see basketballs.)

      The more fundamental limit on the amount of ordinary matter (protons &c.) comes from "big-bang nucleosynthesis". As I (vaguely) understand, the density of ordinary (subject-to-nuclear-reactions, "baryonic") matter in the very early hot universe determines the ratios of helium/deuterium/hydrogen/lithium/photons that were left over once things cooled off. Those ratios - 'primordial abundances' - are more or less measurable and set limits on those early-time densities.

      Result: even if lots of today's ordinary matter were in the form of cold dark invisible basketballs, that matter would have had to be present during Big Bang times too. Observed primordial abundances and known nuclear physics say there was 'way too little of that, no matter what form it takes today, to explain the amounts of 'dark matter' which is detected by its gravity in holding together galaxies and galaxy clusters today.

      (Presumably the mysterious dark matter, *whatever* it is, went through the Big Bang too, but doesn't participate much in nuclear reactions. And, whatever it is, there seems to be about 5x more of it than of all the ordinary matter (visible and in-) put together. Exciting times to do physics, hence the thumbs up...)

  13. Craig (well, I was until The Reg changed it to Craig 16)

    Stars that have never shone...

    We need look no further than Channel 5 these days with Celeb Big Brother for some perfect examples of far closer "stars" that have never shone and have no hope of ever shining. About as much chance of finding intelligent life there as well.

  14. Torben Mogensen

    Oh Be A Fine Girl

    I recall the phrase for remembering the sequence of star types to be "Oh Be A Fine Girl, Kiss Me Right Now, Sweetheart" , but that only works up to "Kiss Me" for the sequence shown in the article, which as LTY instead of RNS after OBAFGKM. Maybe the phrase should be changed to "Oh Be A Fine Girl, Kiss Me Lots This Year"?

    1. Armando 123

      RNS

      R, N, and S stars are not on the main sequence; they are supergiant stars with odd chemistry (strontium absorption lines, anyone?) so both are right.

  15. John Smith 19 Gold badge
    Happy

    But think of the potential

    For a limitless supply of room temperature (depending on where you live) water.

    Of course it *is* 9 LY away.

    1. Gary B.
      Joke

      Distances

      One man's "*is*" is another man's "*is only*" ;-p

  16. NomNomNom

    a

    O, B, A, M, A, K, M, L, T, Y

  17. Matt Piechota

    Slack

    Who knew these guys were astronomers so in tune with modern developements.

    http://www.youtube.com/watch?v=my05ssEhcZQ

    (music video)

  18. Mike Bell
    Windows

    Oh Be A Fine Girl...

    And there was I thinking all this time that it was "Oh Be A Fine Girl Kiss My Ringpiece Now, Slapper!".

    Then again, I've been keeping some odd company in Essex.

    Viewers with a strong constitution may care to Google the meaning of "Dagenham Handshake" (NSFW).

  19. The Grump
    Pint

    Just 9 light years away ?

    ROAD TRIP !!!!!

    Does NASA have the "space" version of beer for the trip ? Unfiltered wheat beer for me, please.

  20. Jim Birch

    Well Done El Reg!

    Thanks for going the extra 9 light years and sending a photographer out to get that high quality snap of our new warm friend.

  21. jimbarter

    "Purple alert! Purple alert!"

    "What's a purple alert?"

    "Well, it's like not as bad as a red alert, but a bit worse than a blue alert -- sort of a mauve alert."

  22. Doug Glass
    Go

    Brown Dwarf

    Emmanuel Luis finally found another job.

  23. TchmilFan

    These are the stars that are closest to me

    Sheldon will have to start again.

    http://thebigblogtheory.wordpress.com/2010/10/21/s04e05-the-desperation-emanation/

  24. Matthew 17

    Y-Dwarf =

    Very large Jupiter.

    1. Lonesome Twin

      replies really don't need a title

      Apparently not - same size but heavier. http://www.nasa.gov/mission_pages/WISE/multimedia/pia14722.html

      1. Nigel 11

        re: replies really don't need a title

        This one doesn't really need a text

  25. Lonesome Twin
    Meh

    Just Mulling...

    ... that this room temperature rock is sustained by a low-grade nuclear reaction at the centre. Much like Terra Ferma herself, shurely?

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