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AUSTRALIAN-ASTRONOMERS
Australian astronomers discover ancient star
SYDNEY, Nov. 5, 2018 (BSS/Xinhua) – A team of astronomers in Australia
have found what could be one of the universe’s oldest stars, almost entirely
made of materials formed by the Big Bang, research revealed on Monday.
Residing in the same part of the Milky Way galaxy as our own solar system,
the star is believed to be up to 13.5 billion years old which is evidenced by
its extremely low metal content, or metallicity.
According to study co-author Dr. Andrew Casey, it was previously believed
that the first stars that formed in the universe could not possibly still
exist today.
“The findings are significant because for the first time we have been able
to show direct evidence that very ancient, low mass stars do exist, and could
survive until the present day without destroying themselves,” Casey said.
The metallicity of stars increases as they are born and die, in a cycle
which results in the creation of more and more heavy metals, with the Earth’s
sun being around 100,000 generations down that line and holding a metal
content roughly equal to 14 Jupiters.
Stars created at the beginning of the universe, however, would have
consisted entirely of elements like hydrogen, helium and small amounts of
lithium – meaning the extremely low metallicity of the newly discovered star,
about the same as the planet Mercury, suggests that it could be as little as
one generation removed from the beginning of the universe.
Up until around 1990, scientist believed that only massive stars could
have formed in the early stages of the universe, and could never be observed
because they burn through their fuel so quickly and die.
However new information has shown that it is possible for low mass stars
to last as long as the 13 billion years since the Big Bang – Red Dwarf stars
for instance, which have a fraction of the mass of the sun, are thought to
live for trillions of years.
BSS/Xinhua/MSY/0959 hrs