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NASA Space Science

NASA Discovers 7th Closest Star 137 says "Scientists using data from NASA's Wide-field Infrared Survey Explorer (WISE) have discovered the coldest class of star-like bodies, with temperatures as cool as the human body. Astronomers hunted these dark orbs, termed Y dwarfs, for more than a decade without success. When viewed with a visible-light telescope, they are nearly impossible to see. WISE's infrared vision allowed the telescope to finally spot the faint glow of six Y dwarfs relatively close to our sun, within a distance of about 40 light-years. 'WISE scanned the entire sky for these and other objects, and was able to spot their feeble light with its highly sensitive infrared vision,' said Jon Morse, Astrophysics Division director at NASA Headquarters in Washington. 'They are 5,000 times brighter at the longer infrared wavelengths WISE observed from space than those observable from the ground.'"
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NASA Discovers 7th Closest Star

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  • Ninja stars (Score:5, Funny)

    by tverbeek ( 457094 ) on Wednesday August 24, 2011 @12:51PM (#37192922) Homepage

    40 lightyears! I hereby dub these "ninja stars", for their ability to sneak up on us like this.

  • Closest or Coldest?

    • They are (relatively) cold. They are also (relatively) close.

    • by Zumbs ( 1241138 )
      Closest and very cold (for a star).
    • Re:Fail? (Score:4, Informative)

      by itchythebear ( 2198688 ) on Wednesday August 24, 2011 @12:59PM (#37193050)

      Nope, no typo.


      The Y dwarfs are in our sun's neighborhood, from approximately nine to 40 light-years away. The Y dwarf approximately nine light-years away, WISE 1541-2250, may become the seventh closest star system, bumping Ross 154 back to eighth. By comparison, the star closest to our solar system, Proxima Centauri, is about four light-years away.

      additional info []

      • Re:Fail? (Score:5, Insightful)

        by jameskojiro ( 705701 ) on Wednesday August 24, 2011 @01:05PM (#37193118) Journal

        Based on how many cold dwarf stars we have found so far, there may be stars like this one within 2 LY or less. In which case they would make for a great candidate for a high speed interstellar probe.

        • Well... considering

          "The [Helios] probes are notable for having set a maximum speed record among spacecraft at 252,792 km/h (157,078 mi/h or 43.63 mi/s or 70.22 km/s or 0.000234c)."

          even our fastest probe is 1/4000 the speed of light, you might be a bit disappointed by the response time.

        • by Anonymous Coward


          You're going to have to define what you mean by a high-speed interstellar probe first. If you mean conventionally fast, I'm going to point you at the voyager program, which is making pretty good time for normal definitions at 17 km/s, and could be out 2 light years in, oh, 34,000 years or so.

          If, on the other hand, you mean significant percentages of c fast (and to make the trip in a reasonable amount of time, you'd have to average at least .1c, which means you have to be capable of going significantly f

          • Unless exotic physics delivers some new way of getting around the light speed barrier, what we're going to need to send probes to even the nearest stars is a craft far more rugged than one we've built now. I'm thinking self-repairing, with lots of raw materials sent with it so it can manufacture spare parts as needed. That, of course, is going to make it very f***ing heavy, which means we're going to need to have some really fantastical way to produce large amounts of energy (the closer you approach c ,

            • by rmstar ( 114746 )

              Unless exotic physics delivers some new way of getting around the light speed barrier, what we're going to need to send probes to even the nearest stars is a craft far more rugged than one we've built now. I'm thinking self-repairing, with lots of raw materials sent with it so it can manufacture spare parts as needed.

              Which means - we won't be going anywhere near another star for the foreseeable future. We are, technologically speaking, like ancient Greeks thinking about sending someone to the moon. We canno

            • by kryliss ( 72493 )

              Self repairing would indicate probably "nano-bots" which in theory could take the broken... whatever and mend it back to original. Like the way our skin is repaired. A lot less material would be needed to take along...... Just my guess.. no data behind it.

          • by toastar ( 573882 )
            IDK, if you had a vasmir pushing at .1G for a year, you would be going about ~.1c, in that case you could be there in 20 years. I think this would be semi-reasonable.
            • Re:Fail? (Score:4, Insightful)

              by CrimsonAvenger ( 580665 ) on Wednesday August 24, 2011 @06:02PM (#37197484)

              IDK, if you had a vasmir pushing at .1G for a year, you would be going about ~.1c, in that case you could be there in 20 years. I think this would be semi-reasonable.

              Hmm, let's do a quick check of the numbers.

              According to Wikipedia, we can reasonably expect 5000 seconds Isp from a VASIMR, but let's assume ten times that, just for grins.

              So, one year (365.24 days) at 0.98 m/s^2 acceleration implies deltaV of 30925 km/s.

              30925 km/s @ 50000 seconds Isp translates to a mass ratio of 2566254356903250866674835623:1.

              So, a 10 kg probe (including drive and fuel tankage) would require 25662543569032508666748356229 kg of reaction mass. Which is about the mass of the Sun...

              So, no, this would NOT be even semi-reasonable....

        • Given the relatively high number of these previously-undetectable stars in just our local(ish) neighbourhood alone.. Might this explain the bulk of that 'missing matter' astronomers and physicists have been looking for?
    • Both, smartass.

    • Re:Fail? (Score:4, Interesting)

      by magarity ( 164372 ) on Wednesday August 24, 2011 @01:17PM (#37193242)

      Closest, yes. Coldest? Maybe - but what if they're inside Dyson spheres and just not radiating much to the outside universe?

      • Re:Fail? (Score:4, Insightful)

        by geekoid ( 135745 ) <dadinportland&yahoo,com> on Wednesday August 24, 2011 @01:29PM (#37193428) Homepage Journal

        Then that would be the most awesome finding ever.

      • by Anonymous Coward

        A Dyson sphere must radiate as much as it receives (from the star inside) or its temperature will rise until equilibrium sets in.

        Using Sol as an example. Sun at 6000K, 600k mls diam, Dyson sphere at 93M mls rad and using Stephan's law for radiation:temp gives a surface temp on the outside of the sphere of about 230deg C. A bit warm and warmer than the article indicates.

        But that's the entire extent of my science on display...

        • What if they constructed their Dyson sphere out of wormhole material and they shunt the energy output to the core of another star, effectively cloaking it? I mean as long as we're talking about shit far beyond our ken, we might as well dream big.

          • Why even go that far? A simple, if rather large, laser is an amazing heat sink, and unless you're right in it's path it would be very very hard to detect.

        • In that case I'd want to increase the diameter of the sphere, since that's a bit to hot. You can assume it's big enough for the ideal temperature for the species that constructed it. This can mean it's 27 C
        • In that case I'd want to increase the diameter of the sphere, since that's a bit to hot. You can assume it's big enough for the ideal temperature for the species that constructed it. Thus it can have almost any temperature that species desires.
  • Telescope? (Score:3, Funny)

    by fuzzyfuzzyfungus ( 1223518 ) on Wednesday August 24, 2011 @12:57PM (#37193018) Journal
    I'm not sure that NASA is taking the most efficient path here: If you want to discover cold, distant objects, any marriage counselor who is a bit flexible about confidentiality should be able to provide you with dozens of them, without any of the trouble of sophisticated infrared astronomy...
  • does this explain the missing mass in the universe or did we allready account for what we found? Hundreds of 'em within a 40ly radius?!
    • It's the packaging material of the computers to do the mass calculation.
    • I was wondering that too... There are more things in heaven and earth than are dreamt of in your string theory, Horatio.

    • by malilo ( 799198 )
      I believe the amount of not-easily-visible ordinary matter in the universe has already been accounted for in our models. We knew sources like this were there. Even at the most optimistic estimates, it is dwarfed by the amount needed to throw off the galaxy rotation curves, the main (but certainly not only) circumstantial evidence for "missing mass" which in turn leads to the idea of dark (non-baryonic, non-interacting) matter.
    • No, it does not. Allowances were made for brown dwarfs, and they do not in any substantial way bump up the amount of observed mass.

      • by Toonol ( 1057698 )
        Although, the allowances were educated guesses. Real data about the frequency of low-mass cold stars is always welcome, and will help refine models. Unless the actual number of cold dwarf stars is off by multiple orders of magnitudes, though, they aren't sufficient to explain the missing mass.

        I tend to think there are massive amounts of planet-sized objects, even smaller and more numerous than dwarf stars, that will be nearly impossible to detect. I don't think they will explain the missing mass, eith
        • My understanding, and I'm only going from memory here, is that even if you account for a very liberal number of brown dwarfs, it still doesn't account for anything but a fraction of the missing mass. I would imagine for them to make a significant impact they would have to be very very very common indeed. Maybe they are, and let's bloody well hope we can get an infrared telescope up into orbit which should be able to start answering the frequency of brown dwarfs out there. Still, I have a suspicion that u

    • > does this explain the missing mass...

      No. Theory predicts these objects.

      > Hundreds of 'em within a 40ly radius?!

      They are very small for stars and don't really account for much mass.

    • At the start of the search for dark matter there were two major categories of potential mater; WIMPs and MACHOs []. The later are large astronomical bodies made of standard matter that are just hard to see, like brown dwarfs, blackholes, and these.

      While hard to see directly, we should be able to observe indirect evidence of their existence due to gravitational lensing of objects behind them, and so forth. Since then many surveys of the sky have been performed, using these techniques. If these objects existed i

  • pfft

    Some star.
  • It means that Sheldon Cooper will need to change the song he sings when he goes down the stairs and you *know* just how much he hates change!

  • by Dr. Spork ( 142693 ) on Wednesday August 24, 2011 @01:21PM (#37193314)
    Isn't it cool that we're working on launching an infrared telescope into space, which might discover that there are lots of such things all over the place? Oh wait, congress is suddenly saying that we can't afford it, even though it costs less than the air conditioning budget for 60 days of the Iraq occupation. (link [])
    • Do you want to be the one to tell a bunch of soldiers that they have to go without air-conditioning for two months?

      • by mjwx ( 966435 )

        Do you want to be the one to tell a bunch of soldiers that they have to go without air-conditioning for two months?

        No, I want to be the one to tell soldiers they can go home.

        Saving a whole bunch of money the US doesn't have in the process is just a plus.

    • never let them see you sweat.
    • by Anonymous Coward

      even though it costs less than the air conditioning budget for 60 days of the Iraq occupation

      You are quoting a retired general, who is now making a living by selling "energy efficient" equipment to Pentagon... Are you really that gullible?..

      • by Anonymous Coward

        It's not about being gullible. It's about throwing out a number that supports a point of view even if the poster knows that the number is wrong. You see tons of it around here, people using numbers and misinformation that is easily disproven but as long as it makes their "side" look good? Not many around here are grounded in the facts.

        Aside from that we could go down a long list of cause and effect but that's not going to get the JWST into space any sooner. Instead of attacking the cause of James We

  • So, this star is cold enough to be the same temperature as the human body? I assume this is at the surface. How the hell does it sustain fusion/fission? It seems to me like its a borderline gas giant or something.
    • by dxkelly ( 11295 )

      Or maybe our gas giants which are producing more heat then they receive from the sun are Y dwarf stars.

    • I think one of the definitions of a brown dwarf is that there is no sustained fusion (I think the larger ones can have limited fusion reactions, but many orders of a magnitude less than even a dim, cool star).

      • Then how exactly is it possible to call it a star at all? Its more like a lone gas giant with possibly a bunch of large moons.
        • Re:Wow (Score:4, Insightful)

          by MightyMartian ( 840721 ) on Wednesday August 24, 2011 @01:57PM (#37193810) Journal

          I think it's a fuzzy definition, and I don't think there's ever been any consensus on calling them stars. Pretty much every article I've read on them refers to them as brown dwarfs (or M, L, Y or T dwarfs), so I'd fault the editor of that one for sloppy use of the word. I don't think you can call any object that doesn't have sustained fission reactions a star, and certainly not one radiating at around the same temperature as a human body.

          • So what letter designation does Jupiter get?

            • It's still a gas giant. I think there has been some debate on this, but at the end of the day they seem to be using Jupiter masses as sort of a cut off for planetary designation, though I don't think there's any hard fast rule. It's still an area of debate about what constitutes a gas giant, a brown dwarf or a star, and as usual, nature isn't making it easy.

        • In more massive brown dwarfs low rate fusion of deuterium (> approx 13 Jupiter masses) and lithium (>60 Mj) is possible. At the low end of brown dwarf mass the distinction with large gas planet is a little blurred, with neither sustaining fusion, being roughly similar in diameter etc.
        • It's not, in any meaningful sense. This is Science By Headline.
    • Stars do not use sustain fission.
    • I think you are getting things upside down here. Hight temperatures inside a star inhibits fusion, that is how a start gets at equilibrium.

      • Very well, however a side effect of fusion is heat. So then the absence of significant heat seems like its possible there is no fusion.
        • Maintaining the entire surface area of a dwarf star (several times bigger than Earth) a hundred of times over the background radiation temperature requires some amount of heat. Certainly there is fusion going there.

    • by Anonymous Coward

      "How the hell does it sustain fusion/fission?"

      It doesn't. By definition, a brown dwarf is not massive enough to sustain the proton cycle, but they are massive enough to have burned their initial supply of deuterium. The larger ones are massive enough to have used up their lithium, too. The mass range is from ~13 Jovian masses to somewhere around 75 to 80 Jovian masses. Brown dwarfs are between super-Jovian gas giants and M-class main sequence stars. The definition on the low end is a little fuzzy,


      • by Gilmoure ( 18428 )

        Why does nature have to have all these fuzzy edges and demarcations. It's almost like things just happened, rather than being planned.

    • It's the Fonz Star.

  • by Fractal Dice ( 696349 ) on Wednesday August 24, 2011 @01:45PM (#37193622) Journal
    At what point do we start to see a picture of the small/cold tail of size distributions? One of the questions that interests me greatly is the frequency of rogue planets in the interstellar medium. If you could see a curve of brown dwarf sizes (weighted by the difficulty of detecting them), it would be fun to just naively extend the graph and see how common gas-giant sized objects would be relative to detectable stars.
    • by pz ( 113803 )

      This is one of the big questions for dark matter. Is dark matter really just non-luminous normal matter that we're just either really bad at detecting or really bad at estimating? Are the assumptions of the distributions of dark matter, as extended presumably from luminous matter, correct? Do more stars just burn out and go cold, rather than go nova, than we think? Sure, these are naive musings from someone with only a highly limited knowledge of the field, but they're fun to think about, and rarely get

      • by Anonymous Coward

        I suppose, if most of dark matter was just this cold stuff, spread everywhere, the sky would appear mostly black, with just a few points of light making it down to Urth.

        • I am not an astronomer, but I think that the sky would be very much like we see it today even if most of dark matter was made of brown dwarfs and other dark objects. Remember that the distances in space are huge.
      • My bet is that most dark matter is made of (dark, duh) objects we haven't managed to see yet, whether they are brown dwarfs, cold gas, black holes...
    • I.e., what is the failure rate of star formation? Maybe I'm missing something, but these Y dwarfs seem a lot like Jupiters.
  • He posits a large number of these dwarf gas giants, and a spacefaring civilization that lives around them: []
  • WISE scanned the entire sky for these and other objects

    I don't think people realize how ludicrous this claim is. To scan the entire sky would require either a wide-angled telescope roughly the size of Mt. Everest and decades, or more likely an average-sized telescope and hundreds of years.

    The sky is big. Really fucking big. Your little telescope can scan at most like 0.000000025% of it at once.

    • Actually it is more like 1/1500000th of the sky at one time. And now that it is done taking a unfathomable (to you) 1.5 million pictures, it has successfully taken a picture of the entire sky.

      Why would you just assume that NASA is lying about its capabilities. Presumably you read about [] the telescope or at least looked at some real info. Are you aware that when you are running a mission you don't use the $100 dollar telescope that parents buy for their kids? Did you realize that a telescope in space can take

    • I think what people around have realized is just what a fucking moron you are.

  • They found 6 of these things very nearby. How big are they? If there are enough of them they could make up for the missing matter that led to the theory of Dark Matter. Or at least reduce it by a large margin.

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