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Astronomer Locates Previously Unseen Neighbor to the Sun

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A diagram of the sun's neighborhood. Clarification: Proxima Centauri was actually discovered in 1915, but its distance was not measured until 1917. Credit: Janella Williams, Penn State University

When NASA launched the WISE satellite in 2009, astronomers hoped it would be able to spot loads of cool, dim objects known as brown dwarfs. Bigger than a planet, a brown dwarf is not quite a star, either—it is too small to sustain the nuclear fusion reactions that turn hydrogen to helium. But it may burn to some degree, using a heavy isotope of hydrogen called deuterium as fusion fuel.

Because brown dwarfs are so dim, it is entirely possible that some of them lie very close to the sun—as close as any known star—and have yet to be discovered. But more than three years after WISE (short for the Wide-Field Infrared Survey Explorer) launched, the map of the sun’s immediate vicinity has remained largely unchanged. Until now.

In a study to appear in the Astrophysical Journal Letters (pdf), Kevin Luhman, an associate professor of astronomy and astrophysics at Pennsylvania State University, announced that he has located a previously unknown denizen of the sun’s neighborhood. Using data from WISE, Luhman has identified a pair of brown dwarfs, bound into a binary system, just 6.5 light-years away. That is nearer to the sun than all but two known star systems, both of which were located more than 95 years ago: the Alpha Centauri triple star system (about 4.3 light-years away) and Barnard’s Star (six light-years).

“I think it is a spectacular find,” WISE principal investigator Edward Wright of the University of California, Los Angeles, wrote in an email, adding that the distance measurement appears robust. “So while this is the third-nearest star (nearly tied for second with Barnard’s star), these are definitely the two nearest known brown dwarfs.”


Image of WISE 1049-5319 from the WISE satellite and the Gemini imagery (inset) that revealed it to be a binary system. Credit: NASA/JPL/Gemini Observatory/AURA/NSF

By extrapolating the orbit back in time for the binary brown dwarf system, known as WISE 1049-5319, Luhman was able to find archival images from other telescopes that registered the object as a moving speck of light as far back as 1978. And he gathered some new imagery of his own—at the Gemini South Telescope in Chile, Luhman caught a glimpse of the object that revealed the speck to be not one but two brown dwarfs locked in a tight orbital dance. Separated by about three times the distance between Earth and the sun, Luhman estimates that the two brown dwarfs circle each other every 25 years or so.

WISE 1049-5319 would make an excellent target for exoplanet hunters, Luhman notes. At such close proximity, any planets that might orbit the brown dwarfs would offer astronomers the rare opportunity to photograph exoplanets and study their properties directly, rather than simply inferring the presence of planets through their influence on the stars that host them. A word about the possibility of extraterrestrial life in such a planetary system: although it is theoretically possible for life to exist on a planet orbiting a brown dwarf, such a world would “suffer a number of critical habitability issues,” according to a 2012 study. Such issues include strong tidal effects from a brown dwarf on the planets near enough to feel its feeble heat and the gradual cooling of the brown dwarf as it ages.

About the Author: John Matson is an associate editor at Scientific American focusing on space, physics and mathematics. Follow on Twitter @jmtsn.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. TonyTrenton 7:43 pm 03/11/2013

    The gray aliens are purported to have very large eyes.

    If they evolved around a red dwarf. Then eyes capable of using low light conditions and inferred would need large eyes.

    Link to this
  2. 2. jtdwyer 5:48 am 03/12/2013

    Nice report of an excellent study. Thanks for the links!

    Link to this
  3. 3. cbarryslough 7:07 am 03/12/2013

    Suck it, Barnard’s Star. 2 Brown Dwarfs at 2 Parsecs trumps 1 main sequence slag at 6 l.y.


    Link to this
  4. 4. cbarryslough 7:09 am 03/12/2013

    Even worse, it’s a low mass red dwarf. Double-suck-it, Barnard’s.

    Link to this
  5. 5. Steven 3:24 pm 03/12/2013

    Binaries are the norm.
    Our solar system is unusual.

    Link to this
  6. 6. wayne nahuy 4:49 pm 03/12/2013

    This is a fine example of fully accepted scientific analysis and its findings are credible this is not something that should be mocked in any way!

    Link to this
  7. 7. hungry doggy 4:56 pm 03/13/2013

    Finding a pair of brown dwarfs just 6-1/2 light years away suggests that brown dwarfs must be common. As other have suggested, perhaps a significant amount of the missing dark matter is locked up in brown dwarfs.

    Not to get real science fictiony here, but conceivable we could reach this brown dwarf someday in the distant future. A one way trip at a tenth of the speed of light would be 65 years.

    Link to this
  8. 8. Wayne Williamson 4:48 pm 03/14/2013

    Cool find…Like hungry doggy, I have to wonder how many more of these are close by. Not interested in the 65 year type of travel, but maybe a probe at 50% light, there in 13 or 14 years;-)

    Link to this
  9. 9. dcary3133 12:39 am 03/15/2013

    Why would we go?

    Link to this
  10. 10. denverjims 1:32 pm 03/15/2013

    Reply to 9. dcary3133:

    “Because it’s there”

    Link to this
  11. 11. dws6969 12:06 am 03/18/2013

    Oh, STOP IT with the “Nuclear fusion” crap already. It has been proven over & over again that stars are NOT nuclear reactors… All you people do is hold the masses back from understanding their reality. One fact you can confirm is that there is NO convection taking place in, on or near the sun. FACT: The Corona is HOTTER than the surface of the sun. FACT: Every planet is magnetically coupled to the sun. FACT: Gravity is NOT the dominate force in the universe, Electricity is. For those of you who want to truly understand your reality please see the Thunderbolts Project. Not only is this group responsible for predicting phenomenon before they are discovered, but they are also able to answer the questions that NASA & mainstream science fails to.

    Link to this
  12. 12. Hubert Boyd 11:18 am 03/19/2013

    dws6969: Please cite references. I do not hold to your opinions, but can be persuaded. Thanks, Hubert Boyd (

    Link to this
  13. 13. edprochak 12:45 pm 03/19/2013

    dws6969: back up your “FACT”s with a little evidence.

    I looked at your web site. The thunderbolts project website is woefully inadequate. It looks more a like yet another site selling yet another new age religion.

    try this: calculate a planetary orbit and demonstrate the advantages of your method versus that of the currently accepted equation of gravity.

    Einstein did it to show his method was better. now it’s your turn.

    Link to this
  14. 14. bucketofsquid 5:58 pm 03/20/2013

    @dws6969 – STOP IT with the crap! That’s it. I’m not selling anything. I think there are too many religions made up from bad story tellers already so we don’t need any more.

    Link to this

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