Saturday , November 28 2020

Australian astronomers discover ancient star – Xinhua



SYDNEY, Nov. 5 (Xinhua) – A team of astronomers from Australia have discovered what could be one of the oldest stars in the universe, almost entirely made up of materials formed by the Big Bang, according to a survey released on Monday.

Residing in the same part of the Milky Way galaxy as our own solar system, it is believed that the star is up to 13.5 billion years, which is evidenced by its very low metal content or metallicity.

According to co-author Dr. Andrew Casey, it was previously believed that the first stars that formed in the universe could not exist today.

"The findings are significant because for the first time we have been able to show direct evidence that there are very old low mass stars that could survive to this day without destroying themselves," Casey said.

The metallicity of the stars increases as they are born and die in a cycle that results in the creation of more and more heavy metals with the Earth's sun about 100,000 generations below that line and maintaining a metal content roughly equal to 14 Jupiteres.

Stars created at the beginning of the universe, however, would have consisted entirely of elements such as hydrogen, helium and small amounts of lithium – which means that the extremely low metallicity of the newly discovered star, roughly the same as the planet Mercury, suggests could be as small as a generation removed from the beginning of the universe.

Until about 1990, the scientist believed that only massive stars could have formed in the early stages of the universe, and could never be observed because they burn their fuel so quickly and die.

However, new information shows that it is possible for low-mass stars to last as long as the 13 billion years since the Big Bang – stars of the Red Dwarf, for example, that have a fraction of the mass of the Sun, will live by trillions. years.


Source link