Hubble captures dying star’s gasp reverberating through nearby galaxy: ScienceAlert
The last screams of light emitted by the dying star are preserved in a series of eerily beautiful images, which slowly echo through the cosmos.
The Hubble Space Telescope captured in spectacular detail the flash of light that followed a massive star that went supernova in 2016 as the glow spread outward over a period of more than five years.
The resulting animation of the merged images is a treasure trove of information about the evolution of dying stars and the dust surrounding the supernova in its parent galaxy, Centaurus A.
“A good everyday analogy is to imagine the finale of a fireworks display – the bright burst of light from a shell at the end of the show will illuminate the smoke from earlier shells still lingering in the area,” says astronomer Stephen Lawrence from Hofstra University in the USA.
“By comparing a series of photographs taken over several minutes, you could measure all kinds of information not directly related to the latest explosion lighting up the scene, things like how many shells had previously exploded, how opaque the smoke was from a given shell, or how fast and in what direction the wind blew.”
Light echoes are a truly stunning phenomenon that can only really be seen from a distance. They are created when something produces a flash of light that radiates into space. If that light encounters a physical barrier, such as clouds of cosmic dust, it will be reflected, arriving at a different time from the initial burst. It’s pretty much the same thing as a sonic echo, but with light. We can use these light echoes to help map and understand spaceand objects within it.
When a supernova was observed in 2016, astronomers took notice and repeatedly returned to the host galaxy, Centaurus A, which are more than 12 million light years away, to see if they can detect changes over time. That persistence paid off. Not only were they able to collect data on the faint light of the supernova, named SN 2016adjthey managed to capture its light echoes.
“The blast wave of this powerful supernova explosion is hurtling outward at over 10,000 kilometers (more than 6,200 miles) per second,” says astronomer Lluis Galbany Institute of Space Sciences in Spain.
“Ahead of this blast wave is an intense flash of light emitted by the supernova, which is what causes the expanding rings we can see in the images. Supernovae are of interest because these cosmic explosions produce many of the heavy elements such as carbon, oxygen and iron, which make up our galaxy , the stars and our planet.”
Centaurus A is a little strange. It is classified as elliptical galaxies, which are typically smooth, oval-shaped galaxies with very little dust and very old stars. However, Centaurus A is very dusty, bursting with star formation and somewhat distorted. These are all signs of a cosmically recent collision with another galaxy, the effects of which have yet to subside.
It is thought that light from a supernova traveling towards Earth would encounter more dust clouds. From our position, we would see this as a series of rings expanding in size. In the five-year observation period, four different light echoes were observed, which meant four dust clouds, each large enough and dense enough to produce a light echo.
These light echoes allowed the researchers, led by astronomer Maximilian Stritzinger of Aarhus University in Denmark, to map the dust near the supernova. Their analysis suggests that the dusty structures contain spaces filled with material too low in density to produce a detectable light echo.
Although we’re pretty excited to check out the image of Centauri A from JWST, which will cut through the dust for us to see the enigmatic heart of the galaxy, the research shows that there are some observations for which Hubble is still king. Since Hubble has been in space for decades, it was able to capture a multi-year observation that provides detailed information about the structure of another galaxy.
“The data set is outstanding and allowed us to produce very impressive color images and animations showing the evolution of the light echo over a period of five years,” Stritzinger says. “It is a rarely seen phenomenon that has only been previously documented in a handful of other supernovae.”
The research was published in The Astrophysical Journal Letters.
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