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Space Science News

UW Astronomers Find A Rare Supernova 'Imposter' In A Nearby Galaxy ( 31

After a star explodes as a supernova, it usually leaves behind either a black hole or what's called a neutron star -- the collapsed, high-density core of the former star. Neither should be visible to Earth after a few weeks. But this supernova -- SN 2010da -- still was.

"SN 2010da is what we call a 'supernova imposter' -- something initially thought to be a supernova based on a bright emission of light, but later to be shown as a massive star that for some reason is showing this enormous flare of activity," said Breanna Binder, a University of Washington postdoctoral researcher in the Department of Astronomy and lecturer in the School of STEM at UW Bothell. Many supernova imposters appear to be massive stars in a binary system -- two stars in orbit of one another. Stellar astrophysicists think that the impostor's occasional flare-ups might be due to perturbations from its neighbor.
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UW Astronomers Find A Rare Supernova 'Imposter' In A Nearby Galaxy

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  • by Tablizer ( 95088 ) on Monday February 15, 2016 @05:46AM (#51509985) Journal

    Star: *Bwuuuurp* Damn! Excuse me! I swallowed a bit too much interstellar gas.

  • The galaxy NGC 300 is 6.07 ± 0.23 Mly away but they are talking about one series of events from less than 5 million years ago, which means we will not know about it for another million years. "they discovered that most nearby stars were created in two bursts — one 30 million years ago and the other less than 5 million years ago."
    • by fnj ( 64210 ) on Monday February 15, 2016 @08:25AM (#51510287)

      I am puzzled by that, too, but also by the whole thing. Just to try to get what they are saying straight, they mean most stars nearby to the location of the phenomenon in question, right? Not nearby to earth?

      The thing that amazes me is that talking about stars only 5-30 million years old. To me that seems like like a newborn baby, not even close to a toddler yet! I mean, the sun is 4.5 billion years old and is expected to last a total of 10 billion years BEFORE becoming a red giant, the end stage.

      • by Anonymous Coward

        Yes, the interesting fact is that the larger the star, the shorter the life. They are the like the rock stars of stars, life fast, die young.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Astronomical times always refer not to absolute, but to point of view times. It's 30 million years ago and 5 million years ago *in our past*, which means in absolute time (which doesn't exist, but for the sake of the argument) it's 36 and 11 MY.

    • by saider ( 177166 )

      If you look at the universe as having one frame of reference (which it doesn't) then you would simply add the 6MY to the 5MY to mean that the stars formed 11MY ago.

      Astronomers refer to events as happening relative to when we observe them, so 5MY ago, those stars' first light would have reached Earth.

      Physics 101

  • by Anonymous Coward on Monday February 15, 2016 @09:23AM (#51510511)

    Many years ago, astronomers noticed that some stars, usually red giants with white dwarfs orbiting them, would flare up every once in awhile. Since oftentimes these stars were, most of the time, too dim to be conspicuous, many of them were uncatalogued at the time that they flared up. So it looked as though new stars were coming into existence, so they were given the name "stella novae" (new stars) which was shortened to "novae" (singular "nova). This was the usual case---matter from a red giant dumps a bunch of hydrogen on a white dwarf, the hydrogen burns very quickly and brightly, and when the reaction is over both stars still exist.

    Then folks realized that some stars blow themselves out of existence. These were named supernovae in contrast to ordinary novae.

    And today we find an ordinary nova in another galaxy, but instead of calling it that, we call it an imposter supernova. I'm offended.

  • by The-Ixian ( 168184 ) on Monday February 15, 2016 @10:43AM (#51510895)

    This seems to imply that the astronomical phenomenon is trying to pull one over of the astronomer.

    This just sounds like hubris.

    Astronomer 1: "As you can see the supernova ..."
    Astronomer 2: "Wait, doesn't a star turn into a black hole or a neutron star after collapse?"
    Astronomer 1: "...... IMPOSTER!"

  • by Anonymous Coward

    SN 2010da was a pretty darned good nova. But supernova? Hardly.

    I wouldn't call it an impostor. Poseur is more like it.

  • by Anonymous Coward

    Supernovae result in either a white dwarf or a neutron star. To date there has been not a single supernova that has been verified to have resulted in a black hole. Given that white dwarfs are quite visible, I can only wonder what the story is really about.

    • A core-collapse supernova is theorized to produce a neutron star. This type of explosion is regarded as the end stage of evolution of a star much more massive than the Sun having enough mass to fuse heavier elements when it exhausts hydrogen form its core.

      A white dwarf is theorized to be the end stage of evolution of a star much like our Sun. Such stars are not massive enough to end in core-collapse after fusing all the light elements. Instead, they end their lives by intense mass outflow resulting in

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