Researchers Witness Extraordinary First Moments Of A Star's Death
About 170 million years ago in a galaxy far, far away, a star exploded. But only now have scientists witnessed the finest details of the star dying.
In a study published on Saturday, an international team of researchers explained a rare galactic moment.
On Februrary 4, NASA's now-retired Kepler telescope in conjunction with ground-based telescopes detected the light emanating from the dying star as it detonated.
A Supernova -- or exploding star -- is one of the largest explosions in the universe and due to their rarity within a galaxy, they're notoriously hard to study.
The international research team including, the Australian National University, have been waiting nearly a decade for a signal of similar to this one.
"Kepler – in its final days before running out of fuel and being retired – observed the minute changes in brightness of the star’s explosion from its very beginnings," said Dr Brad Tucker, one of the lead researchers from the ANU Research School of Astronomy and Astrophysics.
Tucker said the ground-based telescopes detected changes in colour and the atomic make-up of the event.
The ability to actually observe a star dying in such unprecedented detail may help unlock mysteries about how stars explode.
“With the combined data from these telescopes, astronomers achieved what they had hoped for – an unprecedented observation of the onset of a star’s death.”
The event-- known as SN 2018oh-- is a Type Ia supernova, which usually brighten over the course of about three weeks.
Astronomers use this type of supernova to measure the expansion of the universe and probe the nature of "dark energy", which essentially glues the universe together.
Observations of the explosion showed an unexpected rise in brightness which was about three times faster than a typical supernova of this time period, while a gleaming blue hue indicates its extreme temperatures -- billions of degrees hot.
Kepler captured images every 30 minutes from before the explosion started, all the way through to its peak brightness.
Researchers believe the theoretical model which suggests an exploding white dwarf --- what stars like our Sun become after they've exhausted their nuclear fuel -- causes a supernova when it hits a neighboring star.
From the looks of it, this may have been what happened with SN 2019oh.
“It’s possible in the case of SN 2018oh that the shock wave from the exploding white dwarf ran into the companion star, creating an extremely hot and bright halo that accounts for the added brightness and heat we observed,” Dr Tucker said.
If this theory is accurate, the next step is to better understand the frequency and distribution of this kind of Type Ia supernova.
This will help researchers estimate the rate of expansion of the universe, Dr Tucker said.
It seems the perfect ending to what was a star-studded career for the Kepler telescope -- pun completely intended.
It's numerous discoveries changed the way we look at the universe and before it launched in 2009, an observation like this was nearly impossible.
NASA retired Kepler on October 30, after it finally ran out of fuel following nine-and-a-half years of observing the universe.
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