A Yellow Supergiant Progenitor of a Massive Star Supernova in M51

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The uncertainty of science: Astronomers have determined that the star that went supernova in the Whirlpool Galaxy (M51) in June — making it the nearest supernova in 25 years — was a yellow supergiant star, not an aging red supergiant as predicted by theory. From the preprint paper:

Despite the canonical prediction that Type II supernovae arise from red supergiants, there is mounting evidence that some stars explode as yellow supergiants. A handful of Type II supernovae have been observed to arise from yellow supergiants: supernovae 1993J, 2008cn, and 2009kr. The locations of the progenitors on the Hertzsprung-Russell diagram shows clearly that these stars are not located on the predicted end points for single star stellar evolution tracks. In addition, despite arising from supposedly similar yellow supergiant progenitors, these supernovae display a wide range of properties.

The Hertzsprung-Russell diagram is a graph mapping the color of stars against their luminosity. Because color and brightness change as the star evolves over time, the graph is used by astronomers to track the birth, growth, and death of stars. That these yellow supergiants don’t appear to be at “the predicted end points for single star evolution” on the diagram is a serious problem for the theorists who have tried to explain what causes this particular type of supernova.

Which also means astronomers are still unable to tell us what stars in the sky are most likely to go supernova in the future.


  • I’d say that between this revelation and the evidence from the Large Hadron Collider, scientists have a lot of ‘splainen to do.

  • Chris Kirkendall

    True science isn’t postulated on dogma – we should all know that as new information becomes known, theories must sometimes be modified or even scrapped altogether. A good scientist should always continue to challenge prevailing theory – unless you’re Al Gore & think “the science is settled” on GloBULL Warming ! ! We should never, EVER, ignore data that contradicts current thought – we have to be ready to acknowledge that what we thought may have been wrong, or at least not 100% correct.

    But in some ways, it’s exciting when long-held theories turn out to have some holes in them or at least need tweaking to explain the anomolies. Science will NEVER have all the answers, and that’s good – if we ever got to that point, scientists would become almost irrelevant. I think the more we learn, the more apparent it’s becoming that only God knows how everything works. It used to be thought that science & religion were anathema – but science may be in the first stages of proving that we’ll never know everything – behind every door we open are a million new doors with more unanswered questions. But that keeps science new & interesting – if we ever got to the point that we knew it all, it would become boring…

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