For astronomers, astrophysicists and cosmologists, the ability to detect the first stars formed in our universe has always been inaccessible.
The most distant object ever observed was MACS 1149-JD, a galaxy located 13.2 billion light years from Earth that was seen in the Hubble eXtreme Deep Field (XDF) image.
On the other hand, until about 1 billion years after the Big Bang, the universe experienced what cosmologists call the 'dark ages', when the universe was filled with clouds of gas that obscured visible and infrared light.
Fortunately, a team of researchers at the Center for Relativistic Astrophysics at the Georgia Institute of Technology recently ran simulations showing what the first stars looked like.
The study, which describes the results published in the Monthly Notices of the Royal Astronomical Society, was led by Jen Chiaki and John Wise, Researcher and Associate Professor of CfRA (respectively).
They were joined by researchers from the University of Rome, the Astronomical Observatory of Rome, the National Institute of Astrophysics (INAF) and the National Institute of Nuclear Physics (INFN).
Based on the life and death cycles of stars, astrophysicists suggest that the first stars in the universe were very poor in metals. Formed about 100 million years after the Big Bang, these stars consisted of a primordial soup of hydrogen gas, helium, and trace amounts of light metals.
These gases collapsed to form stars 1000 times more massive than our Sun.
Because of their size, stars were short-lived and likely only survived for a few million years. During this time, new and heavier elements appeared in their nuclear furnaces, which then scattered as the stars collapsed and exploded into supernovae.
As a result, the next generation of stars with heavier elements will contain carbon, leading to the designation of carbon-enhanced stars (CEMP).
The composition of these stars, which can be seen by astronomers today, is the result of the nucleosynthesis (fusion) of heavier elements from the first generation of stars.
By studying how these metal-poor stars form, scientists can draw conclusions about what happened in the cosmic 'dark ages' when the first stars formed.
This research is part of a growing area known as 'galactic archeology'.
Just as archaeologists rely on fossils and artifacts to learn more about societies that disappeared centuries or millennia ago, astronomers are looking for ancient stars to study to learn more about those that have long died.
The next step will be to go beyond the carbon characteristics of ancient stars and include other heavier elements in larger models, the researchers said. In doing so, galactic archaeologists hope to learn more about the origin and distribution of life in our universe.
