(ORDO NEWS) — Don’t you hate it when you’re just minding your own business and a star suddenly decides to go supernova? Well, good news: scientists have figured out what these stars look like right before they die.
Massive stars that are the progenitors of neutron stars dim dramatically in the last few months before dying, according to new simulations. explode.
Thus, if a massive star disappears into complete obscurity without fanfare, chances are good that there is a supernova on the horizon.
Red supergiants, with masses between 8 and 20 times the mass of the Sun, are some of the most interesting to watch.
These beasts are nearing the end of their lives and dangerously running out of the fuel they need to sustain nuclear fusion in their cores.
This synthesis provides an external pressure against the internal pressure of gravity. Remove the merge and things get violent. The star explodes, the star’s interiors explode in space, and the stellar core collapses (in most stars).
For the red supergiants considered here, this core develops into a superdense neutron star, somewhere between 1.1 and 2.3 times the mass of the Sun, packed into a sphere only 20 kilometers (12 miles) in diameter.
However, before the big show begins, the star will lose a lot of mass. We don’t understand the mass loss of red supergiants very well on a theoretical level.
By looking at the light and dust resulting from the death of a red supergiant after the fact, scientists have determined that red supergiants emit a lot of gas and dust in the lead up to a supernova explosion, but the time frame in which this happens is unclear.
Could this happen in decades, as past studies suggest, or in less than a year? years, as some other modeling studies predict?
Led by astrophysicist Benjamin Davies of Liverpool’s John Moores University in the UK, a team of researchers used observational data and simulations to reconstruct the evolution of the dying red supergiant.
They ran simulations and found that a huge cloud of material around a star blocks optical light by a factor of 100 and near-infrared light by a factor of 10 just before the star goes supernova.
“Dense material almost completely covers the star, making it 100 times dimmer in the visible range. part of the spectrum,” explains Davis.
“This means that the day before the star explodes, you probably won’t be able to see that it was there.”
To estimate how long the mass loss would take, the researchers went looking for observations. They found several archival images of red supergiants that later went supernova about a year after the image was taken. They say this is evidence that large-scale, obscuring mass loss occurs for at least a year.
This excludes the imminent death of Betelgeuse (although we already knew about this). The mass loss episode that darkened Betelgeuse in 2019 seems to be part of a slower process; according to the latest estimates, the star is 1.5 million years from the supernova.
When that day comes, we’ll now know what to look out for…if we’re still alive.
“Until now, we were able to get detailed observations of supernovae only a few hours after they had already occurred,” says Davis.
“With this early warning system, we can prepare for their observation. in real time to point the world’s best telescopes at the precursor stars and watch them literally being torn apart before our very eyes.”
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