One of the oldest stars of the universe found

11/7/2018 One of the oldest stars in the universe is quietly hiding in the Milky Way about 2000 light-years from Earth.

According to a new study published in The astrophysical journalthe tiny 13.5-billion-year-old red dwarf contains almost no heavy elements, suggesting that it was formed from an almost virgin cloud of remains of matter shortly after the Big Bang. Moreover, since the little star represents only one-seventh of the Sun's mass and is made up of primordial matter, it encourages astronomers to reconsider the demography of the very first stars.

Ancestors

The first stars to form in the universe probably flew about 200 million years after the Big Bang. These first stars were forged in the material available at the time – mainly hydrogen, helium and a touch of lithium.

While these stars lived their lives, they converted their starting elements into increasingly heavy elements, what astronomers call "metals". Some of these early stars eventually exploded as supernovae, which rejected their metals imprisoned in the cosmos. Then the next group of stars is formed from the resulting clouds slightly reinforced with metal. And it continued, each generation of stars enriching the next with more and more metals.

"Our Sun is probably from thousands of short-lived, massive stars who have lived and died since the Big Bang," said lead author Kevin Schlaufman of Johns Hopkins University in a statement. Press. "However, what is most interesting about this star is that she may have only one ancestor who separates her and marks the beginning of everything."

It's small. So what?

It is certainly fascinating to find a star that has been around since the Big Bang, but the small size of the old metal-poor star (succinctly called 2MASS J18082002-5104378 B) is also fascinating.

In general, astronomers believe that the first stars of the universe were extremely massive and led a fairly short life. In fact, until the late 1990s, many researchers thought that the primitive universe could only to form massive stars.

But this vision has slowly evolved over the years, as simulations have become increasingly sophisticated. For example, a Japanese study conducted in 2012 made it possible to perform simulations showing that the formation of low-mass stars in the primitive universe could potentially be triggered by nearby supernova explosions.

Although astronomers do not know exactly how well 2MASS J18082002-5104378 B was formed, "this discovery teaches us that the very first stars in the universe were not all massive stars that had been dead for a long time," says Astrophysicist Andrew Casey of Monash University. at ScienceAlert. "These ancient stars could be formed from very small amounts of material, which means that some of these relics dating back to shortly after the Big Bang could still exist today. This gives us a new perspective for star formation in the primitive universe! "