A red giant star 16,000 light years away appears to be a bona fide member of the second generation of stars in the universe.
According to the analysis of chemical abundance, it appears that it contained elements that were produced in the life and death of only one star in the first generation. Therefore, with his help, we can even find stars of the first generation ever born – none have been found yet.
In addition, the researchers carried out their analysis using photometry, a technique that measures light intensity and offers a new way to find these ancient objects.
“We have reported the discovery of SPLUS J210428.01−004934.2 (hereinafter referred to as SPLUS J2104−0049), a very bad star selected from the narrow band S-PLUS and confirmed by medium and high resolution spectroscopy,” The researchers wrote in their paper.
“This observational proof of concept is part of an ongoing effort to confirm the spectrophotometrically identified low metal filter from narrow band photometry.”
Although we feel we have a pretty good grasp on how the universe grew big explosion For the star-studded glory we know and love today, the first star twinkling in primeval darkness, known as the Population III star, remains a mystery.
The current star formation process provides us with some clues as to how these early stars came together, but until we find them, we are building our understanding on incomplete information.
One of the traces of breadcrumbs is Population Star 2 – several generations after Population III. Of these, the generation that immediately follows the third population is perhaps the most attractive, because it is closest to the third population.
We can identify it by the very low abundance of elements such as carbon, iron, oxygen, magnesium and lithium, which are detected by analyzing the spectrum of light emitted by stars, which contain chemical fingerprints of the elements in them.
This is because, before the stars appeared, there were no heavy elements – the universe is a kind of cloudy soup composed mostly of hydrogen and helium. When the first stars formed, they should have made these stars too – through the process of thermonuclear fusion at the core, heavier elements were formed.
First, hydrogen is put into helium, then helium becomes carbon, and so on to iron, depending on the mass of the stars (the smallest ones don’t have enough energy to melt helium into carbon, ending their lives when they reach this point)). Even the biggest stars don’t have enough energy to melt iron. When the core is entirely iron, it turns into a supernova.
This massive cosmic explosion dumped all this magma into space. In addition, the explosion is very energetic, producing a series of nuclear reactions that form heavier elements, such as gold, silver, thorium, and uranium. Small stars then form from clouds that contain this material and have a higher mineral content than previous stars.
Today’s star – sourdough – has the highest mineral content. (This means that ultimately no new stars have been able to form since then The supply of hydrogen in the universe is limited Happy times.) And stars that were born when the universe was very young have very low mineral content, with the first stars known as super-poor stars or UMP stars.
This UMP is a star of goodwill in Society II, rich in matter from only one supernova population.
Using a scan called S-PLUS, a team of astronomers led by NOIRLab from the National Science Foundation identified SPLUS J210428-004934, and although it doesn’t have the lowest metal grade we’ve found so far (this honor belongs to SMS J0313-6708), It has UMP intermediate star minerals.
It also contains the least amount of carbon astronomers have ever seen in extremely mineral-poor stars. The researchers say this could provide us with important new limits for stellar evolution and an ancestral model for very low metals.
To see how a star could form, they carried out theoretical modeling. They found that the chemical abundances observed in SPLUS J210428-004934, including low carbon and the more natural abundance of UMP stars for other elements, could be better reproduced by high-energy supernovae from single star III stars 29.5 times the mass of the star. Sun.
However, closer modeling still cannot produce enough silicon to precisely duplicate the SPLUS J210428-004934. And they recommend looking for even more ancient stars with similar chemical properties to try to solve this strange contradiction.
“Additional UMP stars identified from S-PLUS photometry will greatly enhance our understanding of Pop III stars and allow the possibility of finding low-mass metal-free stars still alive in our galaxy today,” Write the researcher.
Their paper is published in The Astrophysical Journal Letters.
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