A primitive star sheds light on how the universe learned to breathe

A primitive star sheds light on how the universe learned to breathe
Artistic image of the supernova explosions of the first massive stars that formed in the milky way. The star j0815+4729 was formed from the material ejected by these first supernovae.Gabriel Pérez/SMM (IAC)​

  • Scientists have detected an ancient star with a large amount of oxygen in its atmosphere.
  • During the early days of the universe, there was no oxygen. It was only produced in nuclear fusion occurring at the centre of massive stars.
  • Primitive stars like J0815+4729 could provide clues to how the early production of oxygen led to life on Earth today.
Oxygen is the third most abundant element in the universe and essential for life on Earth — or any planet. The universe went from being without any oxygen in its early days to being flooded with it once the first stars were born.

A team of astronomers have spotted one such primitive star — J0815+4729 — using the Keck Observatory in Hawaii. The star’s chemical composition could provide clues as to how oxygen and other important elements were produced by the first generation of stars.

The study published in The Astrophysical Journal Letters states that the primitive composition of the ancient star indicates that it was formed during the first hundreds of millions of years after the Big Bang.

It’s possible that it was birthed from the material expelled from the very first supernovae of the Milky Way.

"This result is very exciting. It tells us about some of the earliest times in the universe by using stars in our cosmic backyard," said Keck Observatory Chief Scientist John O'Meara.

What are stars made of?
J0815+4729 is over 5,000 lightyears away near a constellation called Lynx. Stars like it are also called ‘halo stars’. "This is due to their roughly spherical distribution around the Milky Way, as opposed to the more familiar flat disk of younger stars that include the Sun," explains Adam Burgasser, a co-author of the study.

The old star is considerably depleted with only 10% of carbon, 8% of nitrogen and 3% of oxygen in comparison to the Sun. But that’s not surprising. Ancient stars like the J0815+4729 are some of the oldest in the universe.

However, the scientists did note something else that was unusual. Aside from the three primary elements, others like calcium and iron were only present in quantities one-millionth that of the Sun.

"Only a few such stars are known in the halo of our galaxy, but none have such an enormous amount of carbon, nitrogen, and oxygen compared to their iron content," said David Aguado, co-author of the study.

Oxygen wasn’t present immediately after the Big Bang. It was created by nuclear fusion reactions occurring deep inside some of the biggest stars in the universe — some even 10 times bigger than the Sun.

To figure out how oxygen was produced in the early day’s scientists need to study J0815+4729 and other primitive stars like it.

"I look forward to seeing more measurements like this one so we can better understand the earliest seeding of oxygen and other elements throughout the young universe," said O'Meara.

See also:
Astronomers ‘accidentally’ discover a new galaxy with as many stars as the Milky Way

Bubbles filled with thousands of stars found in the Milky Way

NASA's planet-hunter uncovers its first world with two stars 1,300 light-years away