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Space Science

Frigid Brown Dwarf Found Only 7.2 Light-Years Away 142

Posted by Soulskill
from the interstellar-stalker-hiding-in-the-bushes dept.
An anonymous reader writes "Astronomer Kevin Luhman just found the 7th closest star to the sun. It's a mere 7.2 light-years away, discovered using NASA's Spitzer and WISE telescopes. How could it exist so close for so long without us knowing? It's a brown dwarf — barely a star at all. 'Brown dwarfs are star-like objects that are more massive than planets, but not quite massive enough to ignite sustained fusion in their cores. Hydrogen fusion is what powers the Sun, and makes it hot; it's the mighty pressure of the Sun's core that makes that happen. Brown dwarfs don't have the oomph needed to keep that going.' This small almost-star is downright chilly at around 225-260 Kelvin. That's -48 to -13 C (or -54 to 9 F). As Phil Plait points out, that's not much different from the temperature in the freezer in your kitchen. He adds, 'It implies this object is very old, too, because it would've been a few thousands degrees when it formed, and would take at least a billion years to cool down to its current chilly temperature. It's hard to determine how old it actually is, but it's most likely 1-10 billion years old. It has a very low mass, too, probably between 3 and 10 times the mass of Jupiter. That's pretty lightweight even for a brown dwarf. And here's another amazing thing about it: It might be a planet. What I mean is, it may have formed around a star like a planet does, then got ejected by gravitational interactions with other planets.'"
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Frigid Brown Dwarf Found Only 7.2 Light-Years Away

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  • by rossdee (243626) on Saturday April 26, 2014 @12:58PM (#46848673)

    No, it might have been a planet once, but its not orbiting a star now so its not a planet.

  • by Viol8 (599362) on Saturday April 26, 2014 @01:02PM (#46848701)

    You try spotting something that cold and not much bigger than jupiter 7 light years away! I'm incredibly impressed they've managed to spot it at all and should be congratulated since it'll barely even register in the infrared never mind visible light.

  • by Anonymous Coward

    I keep hearing about "Dark Matter" as an explanation for how galaxies don't fly apart due to the force generated by their rotation, but I can't help thinking that all that mass we're looking for in galaxies could be stuff like this. Regular matter that just doesn't generate enough heat or light for us to have noticed prior to this.

    Could the question of how galaxies rotate be answered by large quantities of objects such as these?

    • by Blaskowicz (634489) on Saturday April 26, 2014 @01:14PM (#46848797)

      That's part of the MACHO hypothesis regarding dark matter. We could explain away dark matter with trillions of brown dwarfs but that doesn't seem satisfactory for astronomers and cosmologists. For some reason (big bang and cosmic background calculations etc.) we know think that baryonic (regular matter) is only about 4% of the universe's amount of mass-energy and about 25% of non-baryonic dark matter is needed to make it all fit. Not enough baryonic matter to have enough brown dwarfs playing the role of dark matter in/around galaxies.

      • this 2010 preprint [arxiv.org] suggests two types of dark matter.

        We shall follow an approach with two types of dark matter, “Oort” DM in galaxies, composed of baryons, and “Zwicky” DM in galaxy clusters, the true DM.

        suggesting that micro brown dwarfs can't explain everything. The authors posit that Oort DM is composed of MBDs, and Zwicky DM is composed of massive neutrinos.

        But the paper appears not to have been published, so I'm not sure what to think.

      • Actually it's galactic rotation curve stuff: you can show what the observed vs. dark mass difference is by looking at the motion of stars along the plane of the galaxy. And when you start to propose that it's all asteroids and brown dwarfs, you run into problems - because if there were so many out there, then why don't they ever get heated up by all the radiation they'd be absorbing? And why don't they seem to ever meaningfully collide and experience other types of interactions (the famous bullet nebula pic

      • Re: (Score:2, Informative)

        by Anonymous Coward
        It is not just the comological level, but searches have been done for small objects roaming around the galaxy by looking for micro lensing events and occlusion events where rogue planets or objects move in front of other stars. If a large portion of the missing mass needed for the galaxy rotation curve were these planets, you can work out the chances of such objects passing in front of the stars being observed for such effects, and find that we should have seen way more than was actually observed.
      • by Anonymous Coward
        I really can't stand the Dark Matter & Dark Energy theories; it's just the luminescent ether theory in a new guise.

        I strikes me that it's far more likely that our measurements are terrible or we have a basic misunderstanding, rather than inventing a whole new class of matter that has to make up 96% of the universe to make the figures balance.

        Then again I was actually disappointed when the LHC announced a 7-sigma result for the Higgs Boson...
        • by Anonymous Coward

          it's just the luminescent ether theory in a new guise.

          Just not luminescent, or a propagator medium for a wave, and further from the concept of an ether than classical fields.

        • by Anonymous Coward

          I strikes me that it's far more likely that our measurements are terrible or we have a basic misunderstanding, rather than inventing a whole new class of matter that has to make up 96% of the universe to make the figures balance.

          And yet even after we have repeatedly asked you to show your math leading to your hypothisis, you once again refuse to do so!

          Current theory that you say is wrong is the exact same thing that gave us computers, the very tool you are using to state the theory is wrong.
          What has *your* theory given technology lately? One thing? two? Once you catch up to the hundreds of scientific fields that have brought us billions of tangable products - and also explains the missing mass better - we will continue to call yo

      • Re: (Score:2, Interesting)

        Dark matter and dark energy are kludges thrown into an equation because the equation is incomplete.

        Like a formula with 2 unknowns, X and Y, with undefined values for each.

        Dark matter might as well be called "behavior of gravity or a gravity-like force that we don't understand or observations that could be wrong or misunderstood so far".

        Dark energy might as well be called "Looks like we might have expansion if we understand the observations right and since we don't understand this either, let us say ther
        • I totally agree with you. I mean - here's the thing that's always bothered me - if there is SO MUCH F-ing dark matter and dark energy then how is it so mysteriously EVERYWHERE ELSE in the universe but not anywhere near here? If the universe has been permeated by so much of this stuff there's no reason to believe it doesn not permeate our local little section of that universe is there?

          This is why I'm with you: "dark matter" and "dark energy" are really just placeholders signifiying our model of astrophysi

          • It may permeate us. We just don't know.
            If dark matter is really not interacting with anything except that it causes gravity, how would we know? The stuff could be spread out so much between the stars that it is at a not-measurable density.
            Normal matter tends to clump together due to gravity. What if dark matter doesn't do that? We just don't know.

            Having said that: I don't like dark matter and dark energy either. I just don't have enough data to dispute it.

  • It might be a planet. What I mean is, it may have formed around a star like a planet does, then got ejected by gravitational interactions with other planets

    So now not only aren't Planets really Planets, Stars aren't really Stars.
    The IAU and their new speak seriously needs to fuck off.

    What this card carrying member of the IAU **SHOULD** have said is "This likely was a member of a BINARY system that got ejected by gravitational interactions".

    But no... he has to go goose-stepping with his IAU speak and call a star a fucking planet.

    • by Immerman (2627577)

      Well maybe, but if this thing was never fusing was it ever really a star? And if it was fusing, but has now completely stopped, then the question is did it stop being a star while still orbiting it's primary, and thus become a planet first, or did it get ejected as a star and become a planet later? For that matter is there really such a thing as a rogue planet? Planet means wandering star, and we now know that it's only the act of orbitting a star that causes a planet to "wander" across the stellar backg

  • by IDtheTarget (1055608) on Saturday April 26, 2014 @01:07PM (#46848743)

    Sorry for the double-post, didn't realize I wasn't logged in when I posted this previously

    I keep hearing about "Dark Matter" as an explanation for how galaxies don't fly apart due to the force generated by their rotation, but I can't help thinking that all that mass we're looking for in galaxies could be stuff like this. Regular matter that just doesn't generate enough heat or light for us to have noticed prior to this.

    Could the question of how galaxies rotate be answered by large quantities of objects such as these?

    • by aardvarkjoe (156801) on Saturday April 26, 2014 @01:16PM (#46848805)

      The Wikipedia article on dark matter [wikipedia.org] discusses this in depth. Although I'm no astrophysicist and can't vouch for the article's accuracy, it does outline some of the reasons why those studying it believe that objects like this cannot account for the amount of dark matter required to explain how galaxies behave.

    • by idji (984038) on Saturday April 26, 2014 @01:30PM (#46848879)
      Your question is whether Dark Matter could be real and observed MACHOs [wikipedia.org].
      The other main option is that Dark Matter could be hypothetical WIMPs [wikipedia.org]
      Numerous experiments have ruled out MACHOS as making up the bulk of Dark Matter. The missing mass problem is not solved by MACHOs.
      At the moment the WIMPS are beating the MACHOS.
      See also History of the search for Dark Matter [wikipedia.org]
    • These object are composed of ordinary every day matter so they interact with electromagnetic radiation. For instance, this particular object was detected by infrared radiation.

      Observation of the rest of the universe shows more gravitational interaction than electromagnetic interaction versus what you would expect from ordinary matter. "Dark Matter" and "Dark Energy" are proposed particle types that do not interact electromagnetically but to interact with other forces. Other proposals model the forces differ

  • My personal experiences, have been very much, the opposite.
  • Kudos for writing 225-260 Kelvin and not 'degree Kelvin' or 'Kelvins' in the summary. Slate f'ed up though. They wrote 'Kelvins'. I have seen even reputable scientific writings using degrees prefix with Kelvin. It's very disheartening to see that even some scientists don't get it that you don't use degrees when talking about absolute temperature.
    • by Jeremy Erwin (2054) on Saturday April 26, 2014 @01:43PM (#46848935) Journal

      From an authoritative and current source [bipm.org]

      It follows that the thermodynamic temperature of the triple point of water is exactly 273.16 kelvins, Ttpw = 273.16

      If the BIPM can't be bothered,I don't see why the rest of us should follow your prescription.

      • And since

        And to head off your objection.

        Readers should note that the official record is always that of the French text.

        The french standard says

        Il en résulte que la température thermodynamique du point triple de l’eau est égale à 273,16 kelvins exactement, Ttpw = 273,16 K.

        french original [bipm.org]

        The first obligation of a pedant is to be technically correct.

    • by AthanasiusKircher (1333179) on Saturday April 26, 2014 @02:15PM (#46849093)

      Kudos for writing 225-260 Kelvin and not 'degree Kelvin' or 'Kelvins' in the summary. Slate f'ed up though. They wrote 'Kelvins'.

      Umm, sorry, but you're wrong. As an SI unit, a "kelvin" (yes, with a lowercase k) is pluralized using the same grammatical rules as others (e.g., volts, ohms, etc.). Its abbreviation is an uppercase K.

      So, "225-260 kelvins" or "225-260 K" is correct, according to official SI standard.

      If you want to be pedantic, be sure you have a clue concerning what you're talking about.

      (And regardless, I think this is a rather stupid thing to get too pedantic about. The previous standard, before 1968, referred to it as "degrees Kelvin" just like all the other temperature standards. I understand that the SI conventions are trying to maintain consistency across all units, but it's weird when that also results in breaking consistency with all other units that deal with the same type of measurement. I'm not saying it's wrong, and official scientific documents shoudl get it right, but in normal language... I think this is a rather silly think to get worried about, since it actually breaks other linguistic conventions of standard language.)

      • And by the way, before somebody starts objecting to my comment about common language usage by saying that "kelvins" and not "degrees Kelvin" represents an absolute scale or something, rather than a "degree" -- that's a bogus argument. Anyone who works with "degrees Rankine" knows that (1) it's always Rankine, not rankine, (2) it's never pluralized as "rankines" as "kelvins" is, (3) the abbreviation should contain the degree symbol, and (4) the only people who say "Rankine" instead of "degrees Rankine" are
  • Could it be the Nemesis Star that orbits the Sun from far away, and maybe responsible for periodic extinctions here on earth? Probably not. :)

  • Traveling at 25 m/s, the speed of the current fastest man made object, it would take 55,885 years to reach this star. It's understandable why we haven't noticed it till now.

  • by Lew Pitcher (68631) on Saturday April 26, 2014 @02:24PM (#46849133) Homepage

    Two elements of TFA caught my eye:

    1. The object radiates at "around 225 – 260 Kelvins", or (if I got the math correct) 12.878971111111
      micrometers
    2. the object "has a very low mass, too, probably between 3 and 10 times the mass of Jupiter".

    Together, these figures are within the range for a type I (or, maybe even a type II) Dyson sphere.
    And, it is only 7.2 light years away?

    Yes, it is very probably the Brown Dwarf that the astronomers think it is.
    But, imagine. It could be a Dyson sphere; our first evidence of advanced life beyond the earth.

    • I doubt it because we would be deluged with holidaying spherians every long weekend. Earth beaches are the best. Also the construction process would have generated a lot of debris. Seriously, it is too close not to be noticed as such. If they were humans there would be trillions of them in there. Even if it was a ringworld sort of thing with a collapsed civilisation, there would be ships coming past and making radio noise, exhaust, etc.

      • by ltbarcly (398259)

        I doubt it because we would be deluged with holidaying spherians every long weekend. Earth beaches are the best. Also the construction process would have generated a lot of debris. Seriously, it is too close not to be noticed as such. If they were humans there would be trillions of them in there. Even if it was a ringworld sort of thing with a collapsed civilisation, there would be ships coming past and making radio noise, exhaust, etc.

        Why do you think you have any idea what we would see or not see?

        Imagine you were living with circa 1800 AD technology, and were looking for evidence of another civilization with circa 2014 technology. Keep in mind that this 200 year difference is nothing compared to the difference between modern technology and the technology of a race capable of building a Dyson sphere.

        Perhaps you would use a rudimentary telescope to look out to sea. You would rule out any ships, since the weird objects you see don't have

        • Imagine you were living with circa 1800 AD technology, and were looking for evidence of another civilization with circa 2014 technology. Keep in mind that this 200 year difference is nothing compared to the difference between modern technology and the technology of a race capable of building a Dyson sphere.

          The existence of the advanced civilisation would be obvious to us because they'd be in our villages raping our women. So maybe aliens wouldn't be doing precisely that, but if they are anything like us they would be curious and hungry for resources.
          I think the it is significant that the only debris found on the lunar surface was put there by humans. Any sort of exploration of our solar system would have left debris, garbage, broken vehicles, etc. And if somebody invested in a Dyson sphere only 7 light years

    • It might not be a Sphere itself, but my mind went there as well. If you have something 'refrigerator warm' in the middle of space, you can extract useful energy from it, and especially when the damn thing isn't on fire, materials. I'm thinking of some sort of sphere with millions of space elevators dangling down from the inside to the planet's surface, or something of that nature.

      [insert hundreds of pages of math]

      Perhaps a decent place for humans to do "My First Space Sphere" without all the stresses invo

    • A Dyson sphere might be radiating at 2.725 K, the microwave background temperature of the Universe, as the beings in it might have found a way to violate the 2nd law, via such things as a molecular ratchet, or brownian ratchet, and the Universe might be full of 2.725 K radiating things. The best way to hide a Dyson sphere is to make it the same temperature as the surroundings, and if it's not the same temperature, you may assume it's not a Dyson sphere.

      As far as the warm temperature goes, we have to look
      • Also life even on this planet does not require a star, or light and photosynthesis, just a sufficiently high head, or "waterfall" of caloric, i.e. a large temperature gradient. See the Wikipedia page on Hydrothermal vent, http://en.wikipedia.org/wiki/H... [wikipedia.org].
      • by iggymanz (596061)

        the ratchets have been proven to be ineffective by Feynman for escaping the second law, they won't work as posited.

        Saying all life must follow some guidelines based on earth's composition or common factor of its life forms is using a sample size of one.

    • It can't be a Dyson sphere because it is not big enough to encompass a star.
      It could theoretically be an artificially made object of similar properties. However, that is IMHO less likely than an ancient brown dwarf or a rogue planet.

  • by iggymanz (596061) on Saturday April 26, 2014 @02:45PM (#46849225)

    Brown dwarves are not stars, this astronomer did not find a star nor the 7th furthest star from the Sun. Brown dwarves are known as "sub-stellar objects". No fusion, no star.

  • it may have formed around a star like a planet does, then got ejected by gravitational interactions with other planets.

    But if Jupiter interacts with anything, Jupiter isn't going to get ejected. The remaining object must have been a sizeable star.
    This star must be warm deeper down. I wonder if it is a good place for life.

  • That's amazing! That is the exact name I had for my ex wife!

  • If this [physicsforme.com] is correct, then why not.

  • A cold brown dwarf star?
    Did they name it "Gary Coleman"?

  • I say we completely ignore it from now it it's not really worthy of our attentions is it within its' rotten miserable failure to be anything important?

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