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Thread: Closest black hole found

  1. #1
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    Closest black hole found

    ESO.org

    A team of astronomers from the European Southern Observatory (ESO) and other institutes has discovered a black hole lying just 1000 light-years from Earth. The black hole is closer to our Solar System than any other found to date and forms part of a triple system that can be seen with the naked eye. The team found evidence for the invisible object by tracking its two companion stars using the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. They say this system could just be the tip of the iceberg, as many more similar black holes could be found in the future.
    I read elsewhere that the previous closest was around 3000 LYs away.

    Link to the paper

    Abstract

    Several dozen optical echelle spectra demonstrate that HR 6819 is a hierarchical triple. A classical Be star is in a wide orbit with an unconstrained period around an inner 40 d binary consisting of a B3 III star and an unseen companion in a circular orbit. The radial-velocity semi-amplitude of 61.3 km s−1 of the inner star and its minimum (probable) mass of 5.0 M⊙ (6.3 ± 0.7 M⊙) imply a mass of the unseen object of ≥4.2 M⊙ (≥5.0 ± 0.4 M⊙), that is, a black hole (BH). The spectroscopic time series is stunningly similar to observations of LB-1. A similar triple-star architecture of LB-1 would reduce the mass of the BH in LB-1 from ∼70 M⊙ to a level more typical of Galactic stellar remnant BHs. The BH in HR 6819 probably is the closest known BH to the Sun, and together with LB-1, suggests a population of quiet BHs. Its embedment in a hierarchical triple structure may be of interest for models of merging double BHs or BH + neutron star binaries. Other triple stars with an outer Be star but without BH are identified; through stripping, such systems may become a source of single Be stars.
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  2. #2
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    Quote Originally Posted by Swift View Post
    I read elsewhere that the previous closest was around 3000 LYs away.
    I think this is the only stellar mass black hole discovered that doesn't have a hot accretion disk... except for a few candidates much further away, but unknown distance discovered by OGLE.
    Forming opinions as we speak

  3. #3
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    The star is in Celestia, at 760ly away.
    I suspect that figure is somewhat shaky, since the star is double and its components are moving quite fast (this movement is the clue that led them to suspect the existence of the black hole).

  4. #4
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    I saw a headline about this somewhere which read along the lines of "Black hole found in visible galaxy". Hmmm, the Milky Way is pretty visible and we've known about its black hole for some time now.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  5. #5
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    Quote Originally Posted by Trebuchet View Post
    I saw a headline about this somewhere which read along the lines of "Black hole found in visible galaxy". Hmmm, the Milky Way is pretty visible and we've known about its black hole for some time now.
    Oh! It was Wikipedia! Actual headline:
    Astronomers announce the discovery of the first black hole located in a star system visible to the naked eye (pictured).
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

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