(ORDO NEWS) — The last bursts of light emitted by the dying star are preserved as a series of eerily beautiful images that slowly echo across the cosmos.
The Hubble Space Telescope captured a flash of light in great detail. which followed the massive star’s 2016 supernova as the glow spread outward for more than five years.
The resulting animation from images stitched together is a treasure trove of information about the evolution of dying stars and the dust surrounding the supernova in its home galaxy, Centaurus A.
“A good everyday analogy is to imagine the end of a firework the bright flash of light from a projectile at the end of the show will ignite the smoke from earlier projectiles that still remains in the area,” says astronomer Stephen Lawrence of Hofstra University in the US.
“By comparing a series of photographs taken over the course of a few minutes, you can get all kinds of information that is not directly related to the most recent explosion that illuminated, for example, how many shells exploded earlier, how opaque the smoke from a given shell is, or at what speed and in what direction the wind was blowing.
Light echoes are a truly stunning phenomenon that can only really be seen from afar. They occur when something produces a flash of light that radiates into space. If this light encounters a physical barrier, such as clouds of cosmic dust, it will bounce back, arriving at a different time from the original burst.
This is almost the same as sound echo, but with light. We can use these light echoes to map and understand space and the objects within it.
When a supernova was observed in 2016, astronomers took notice and repeatedly returned to the host galaxy Centaurus A, more than 12 million light-years away, to see if they could observe changes over time.
This perseverance paid off. They managed not only to collect data on the attenuation of light from a supernova called SN 2016adj, but also to record its light echoes.
“The blast wave from this powerful supernova explosion is rushing outwards at over 10,000 kilometers (over 6,200 miles) per second,” says astronomer Luis Galbani of the Institute of Space Sciences in Spain.
“Ahead of this blast wave is an intense burst of light emitted by a supernova, and this is what causes the expanding rings we see in the images. Supernovae are of interest because these cosmic explosions produce many of the heavy elements such as carbon, oxygen, and iron that make up our galaxy, stars, and our planet.”
Centaurus A is a little weird. It is classified as an elliptical galaxy, which is usually smooth, oval-shaped galaxies with very little dust and very old stars. However, Centaurus A is very dusty, emits star formation, and is slightly curved.
All these are signs of a cosmically recent collision with another galaxy, the consequences of which have not yet been eliminated.
It is believed that when the light from the supernova went to the Earth, he met numerous clouds of dust. From our position, we would see it as a succession of rings increasing in size.
Over a five-year observation period, four distinct light echoes were observed, that is, four dust clouds, each of which was large and dense enough to produce a light echo.
These light echoes have allowed researchers led by astronomer Maximilian Stritzinger of the University of Aarhus in Denmark to map the dust near the supernova. Their analysis shows that in dusty structures there are spaces filled with material whose density is too low to produce a noticeable light echo.
While we’re thrilled to see JWST’s image of Centaurus A tearing through the dust to reveal the galaxy’s enigmatic heart, the study shows there are some observations for which Hubble is still king.
Since Hubble has been in space for decades, it has been able to make a long-term observation that provides detailed information about the structure of another galaxy.
“The dataset is amazing and has allowed us to get very impressive color images and animations showing the evolution of the light echo over a five-year period,” says Stritzinger. “This is a rarely observed phenomenon, previously recorded only in a few other supernovae.”
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