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posted by Fnord666 on Sunday March 26 2017, @02:04PM   Printer-friendly
from the I'm-not-a-star dept.

Astronomers have discovered the most massive and "purest" known brown dwarf:

An international team of astronomers has identified a record breaking brown dwarf (a star too small for nuclear fusion) with the 'purest' composition and the highest mass yet known. The object, known as SDSS J0104+1535, is a member of the so-called halo -- the outermost reaches -- of our Galaxy, made up of the most ancient stars. The scientists report the discovery in Monthly Notices of the Royal Astronomical Society.

[...] Located 750 light years away in the constellation of Pisces, SDSS J0104+1535 is made of gas that is around 250 times purer than the Sun, so consists of more than 99.99% hydrogen and helium. Estimated to have formed about 10 billion years ago, measurements also suggest it has a mass equivalent to 90 times that of Jupiter, making it the most massive brown dwarf found to date. It was previously not known if brown dwarfs could form from such primordial gas, and the discovery points the way to a larger undiscovered population of extremely pure brown dwarfs from our Galaxy's ancient past.

Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object (open, DOI: 10.1093/mnras/stx350) (DX)


Original Submission

 
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  • (Score: 2, Informative) by Anonymous Coward on Sunday March 26 2017, @11:48PM (2 children)

    by Anonymous Coward on Sunday March 26 2017, @11:48PM (#484476)

    In case you were wondering (as I was)...

    Smallest [ignited] Star [yet discovered] in the Universe [bellaonline.com]

    to find the smallest red dwarf and test the mass limit [...] a group at Georgia State University in the USA, led by Sergio Dieterich, took up the challenge [...]

    The smallest star so far [is] red dwarf 2MASS J05233822-1403022. [...] The teensy star, about the size of Saturn, has a mass less than 8% of the mass of the Sun. Its temperature of 1800 °C is less than a third of the Sun's 5600°C.

    Nonetheless, the models predict that the mass limit is around 1400° C. So 2MASS J0523-1403 probably isn't the smallest star

    -- OriginalOwner_ [soylentnews.org]

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  • (Score: 2) by takyon on Monday March 27 2017, @02:28AM (1 child)

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Monday March 27 2017, @02:28AM (#484500) Journal

    That should be about 83 Jupiter masses. Which means some brown dwarfs have larger masses than the smallest red dwarfs.

    --
    [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 2, Informative) by laserfusion on Monday March 27 2017, @08:49PM

      by laserfusion (1450) on Monday March 27 2017, @08:49PM (#484862)

      TRAPPIST-1 is also smaller than this brown dwarf, at 84 Jupiter masses [wikipedia.org].

      The TFA says that the metallicity of a brown dwarf affects the minimum mass for hydrogen fusion. That's one reason for the overlap between brown dwarf and red dwarf sizes.