The oldest star discovered - 13.5 billion years old

Astronomers have allegedly discovered the oldest star in the universe and thus broke the hypothesis that small stars did not form in the early universe. The celestial body is made of the material released after the big bang

The discovery of the 13.5 billion year old star may indicate the existence of other small stars with low mass and metal density - these are the first stars of the early universe. The recently observed star is unique because it resides in the thin and distant layer of our galaxy (in this region our sun also resides). Because the star is so old, researchers believe our galactic cluster is more than 3 billion years older than previously thought.

Heavy elements are born

The first stars formed after the Big Bang contain mostly hydrogen, helium, and a little lithium. The internal gravitational forces of the star produce tremendous pressure in their core and create heavier elements in the process of nuclear fusion. Thus, in fact, heavy elements were created in the universe and dispersed at the end of the star's life in a process called supernova (for stars with a sufficiently large mass). After the material is dispersed in space, it is accumulated back with the help of gravity into new stars with higher metallicity. This periodicity indicates that young stars must contain a relatively high concentration of metallicity while ancient stars contain a tiny percentage of metals in them. The newly discovered star contains a relatively low concentration of metals that matches the profile of ancient stars. By comparison, the star's metal concentration is similar to the metal profile of the planet Mercury, while our Sun, the result of many stars that died before it, has a metal concentration 14 times greater than the planet Jupiter.

Astrophysicists have previously discovered 30 stars with a similar metal profile with a mass close to the mass of the Sun, but the Johns Hopkins researchers who published the latest discovery showed that the mass of the new star is 10 times smaller than our Sun (about 14 percent to be exact).

about the surprising discovery

The discovery began when researchers from Johns Hopkins looked at an ancient bright star discovered by another team of researchers. The research led them to conclude that the star belongs to a binary system - that is, it is "paired" with another star that both rotate around a common center. The second star discovered is much weaker than the observed star and even predates it. The researchers were able to measure the mass of the star by the tidal forces exerted by its partner in the binary system. The researchers measured the concentration of the metals based on the light spectrum emitted by the star and thus estimated the age of the star. Since the 90s, researchers believed that only massive stars could form immediately after the Big Bang. Because their estimated mass is so large, the nuclear fuel burns relatively quickly, so scientists believed they were unobservable. At the same time as technological progress, simulations became more sophisticated and computer models hinted that low-mass stars may be discovered from the early universe and indeed the latest observation strengthens the claim. Unlike giant stars, the life time of small stars is much longer. Red dwarfs for example can live for trillions of years.

The findings were published in the journal  The Astrophysical Journalby researchers from Johns Hopkins in the United States.

for the scientific article