An “early warning” system has been developed by astronomers from Liverpool John Moores University and the University of Montpellier to tell people when a huge star is ready to end its life in a supernova explosion.
The paper was published in the Royal Astronomical Society‘s Monthly Notices.
In this new study, scientists found that big stars in their final stage of life, the so-called “red supergiant phase,” can abruptly become about a hundred times fainter in visible light in the final few months before they die. These stars are typically between 8 and 20 solar masses.
This dimming is brought on by a sudden buildup of debris surrounding the star that blocks off its light.
Prior to this discovery, it was unknown how long it took for the star to accumulate this stuff.
For the first time, scientists have created computer simulations of what red supergiants would appear like when they are wrapped in these pre-explosion “cocoons.”
Images of stars that exploded roughly a year after the photograph was captured can be found in old telescope archives. In these photographs, the stars appear normal, indicating that they have not yet formed the theorized circumstellar cocoon.
This indicates the cocoon is constructed in a very short amount of time, likely under a year.
Lead author of the study and professor at Liverpool John Moores University, Benjamin Davies, adds:
“The dense material almost completely obscures the star, making it 100 times fainter in the visible part of the spectrum. This means that the day before the star explodes, you likely wouldn’t be able to see it was there.”
Until recently, he continues, “we’ve only been able to get detailed observations of supernovae hours after they’ve already happened. With this early-warning system we can get ready to observe them real-time, to point the world’s best telescopes at the precursor stars, and watch them getting literally ripped apart in front of our eyes.”
Image Credit: European Southern Observatory/L. Calçada
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