An unusual supernova allows astronomers to peek into the cosmic past

An international team of researchers has made new observations of an unusual supernova, finding the most metal-poor stellar explosion ever observed.

According to a new study, this rare supernova, called 2023ufxoriginated from the collapse of the core of a red supergiant star, which exploded on the outskirts of a nearby dwarf galaxy.

The results of the , recently published in The Astrophysical Journalshowed that observations of this supernova and the galaxy in which it was discovered have a low metallicitymeaning they don’t have an abundance of elements heavier than hydrogen or helium.

Os metals produced in supernovae they give information about their properties, including how stars evolve and die.

So learning more about its formation can tell astronomers a lot about the state of the Universe when it beganespecially since there were essentially no metals at the time of his birth, he said Michael Tuckerlead author of the study and member of the Center for Cosmology and Particle Astrophysics at Ohio State University, USA.

“If someone wants to predict how the Milky Way came into existence, they need to have a good idea of ​​how the first exploding stars fed the next generation“, Tucker said. “Understanding this gives scientists an excellent example of how the first objects affected their environment.”

As dwarf galaxies, in particularare useful local analogues to the conditions scientists expect to find in the early Universe. Thanks to them, astronomers know that, although the first galaxies were poor in metalsall the large, bright galaxies near the Milky Way have had plenty of time for stars to explode and increase their metal content, Tucker said.

The metallic content that a supernova has also influences aspects such as number of nuclear reactions it can have or the time your explosion remains bright.

It’s also one of the reasons why many low-mass stars are occasionally at risk of turning into black holes.

Although the event observed by Tucker’s team is only the second supernova found with low metallicity, what is most unusual is its location relative to the Milky Way, Tucker said.

Normally, any metal-poor supernova that astronomers expected to find would probably be too tenuous to be seen from our Galaxy, due to its distance.

Now, thanks to the advent of more powerful instruments like NASA’s James Webb Space Telescope, detecting distant metal-poor galaxies has become exponentially easier.

“There aren’t that many metal-poor places in the Near Universe, and before JWST, they were difficult to find,” Tucker said.

But the sighting of SN 2023ufx turned out to be a happy accident for researchers. New observations of this particular supernova have revealed that many of its properties and behaviors are clearly different from other supernovae in nearby galaxies.

For example, this supernova had a period of brilliance which remained stable for about 20 days before decreasingwhile the glow of their metal-rich counterparts typically lasts about 100 days.

The study also showed that it was ejected a large amount of material moving quickly during the explosion, suggesting that it must have been spinning very quickly when it exploded.

This result implies that metal-poor, rapidly rotating stars must have been relatively common during the early times of the Universe, Tucker said.

His team’s theory is that the supernova likely had weak stellar winds – streams of particles emitted by the atmosphere of the star – that led her to cultivate and release so much energy.

Overall, the observations lay the groundwork for astronomers to better investigate how metal-poor stars survive in different cosmic environments and may even help some theorists to model the behavior of supernovae in the early Universe more accurately.

Future studies could aim to determine whether the supernova was larger at some point, either because it was a supermassive stareither because its materials have been withdrawn by a binary companion yet to be discovered.

Until then, researchers will have to wait for more data to become available.

“We’re so early in the JWST era that we’re still discovering a lot of things we don’t understand about galaxies,” Tucker said. “The long-term hope is that this study will serve as a benchmark for similar findings.”