Podcaster: Richard Drumm
Title: Space Scoop:Clearing the Fog Around Exploding Stars
Organization: 365 Days Of Astronomy
Link : astrosphere.org ; http://www.unawe.org/kids/unawe1822/
Description: Space scoop, news for children.
These truly colossal stars are called “red supergiants”. They’re stars in the very last stages of their lives, shortly before they blow up in a spectacular supernova explosion.
Supernovae are the largest explosions in the Universe. They shine with the brightness of 10 billion suns and give off more energy in a few days than our Sun will in its entire lifetime.
When a red supergiant goes supernova, something special may happen: a brief but brilliant flash of light might be seen before the full explosion. This is called the “shock breakout”.
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Transcript:
This is the 365 Days of Astronomy Podcast. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.
Clearing the Fog Around Exploding Stars
Looking up at the night sky, it’s hard to believe that each of the small, twinkling points of light is a giant ball of hot, glowing gas. Well, plasma. But you get the idea.
Even the smallest of these stars is several times bigger than Earth, while Earth’s orbit around the Sun could fit comfortably inside the largest of them.
These truly colossal stars are called “red supergiants”. They’re stars in the very last stages of their lives, shortly before they blow up in a spectacular supernova explosion.
Supernovae are the largest explosions in the Universe. They shine with the brightness of 10 billion suns and give off more energy in a few days than our Sun will in its entire lifetime.
When a red supergiant goes supernova, something special may happen: a brief but brilliant flash of light might be seen before the full explosion. This is called the “shock breakout”.
The shock breakout is expected to only last about 20 minutes, so catching it isn’t easy. But back in 2011 and 2016 it may have been seen for the very first time in visible light.
In 2011 the Kepler Space Telescope captured a light curve of supernova KSN 2011d, in galaxy KIC10649106, in the constellation Cygnus.
The brightness data was gathered by Kepler every 30 minutes, which makes calculating the brightness of a 20 minute long event problematical. There was, however, one data point that was significantly brighter than a smooth rise would have predicted.
This bright data point is likely the shock breakout.
Then 5 years later, on September 20th, 2016, amateur astronomer Victor Buso of Rosario, Argentina captured many 2 minute long still images of SN 2016gkg.
He got images before and during a shock breakout in the galaxy NGC 613, 80 million light years away in the constellation Sculptor.
However, he didn’t know at the time what he had. He stopped taking data too soon. After the imaging session was over he saw the images and knew that he had detected the start of a supernova.
The pretty spike that all the news outlets carried at the time isn’t Victor’s data, it’s the computer simulation of the light curve. Some astronomers are unconvinced that there was a breakout flash.
However, astronomers wanting to study the shock breakout more recently have been less lucky. Specifically the Forster/Moriya Chilean & Japanese team, that despite watching patiently as 26 red supergiants exploded, didn’t manage to catch a single flash of light.
To find out why the shock breakout has mysteriously disappeared, they turned to technology. Powerful supercomputers are able to create detailed simulations of supernova explosions.
They created over 500 models, each one with a very subtle difference, such as the brightness or mass of the star.
Before long, it became clear that one ingredient caused the models to match real observations better than any other – a layer of star dust. This dust is found around many supernovae and traps the light from the shock breakout, hiding it from our telescopes.
Understanding these violent events might not seem important, but it actually tells us how material is spread across our galaxy.
All the silver, nickel and copper on Earth and even many elements in our bodies came from the explosive death of stars, the iron in our blood, the calcium in our bones, too. Life exists because of supernovae!
Without them we simply wouldn’t exist!
Hey, Here’s A Cool Fact:
When a red supergiant goes supernova, it’s known as a Type II core collapse supernova.
These begin when the internal furnace of the star runs out of fuel, causing the core to collapse as gravity takes over and leading to a titanic explosion.
What happens inside a supernova is a separate story for another time. It’s awesome and awesomely complex!
Thank you for listening to the 365 Days of Astronomy Podcast!
End of podcast:
365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Astronomical Society of the Pacific. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. This year we will celebrates the Year of Everyday Astronomers as we embrace Amateur Astronomer contributions and the importance of citizen science. Join us and share your story. Until tomorrow! Goodbye!