These remnants were found in a gas cloud located 13 billion light-years away, which could potentially be the resting place of some of the oldest stars in existence.
According to the Vietnam Academy of Science and Technology, astronomers have recently detected the remnants of early stars. The chemical signatures observed in these distant remnants (objects over 13 billion years old) exhibit significant differences compared to those of younger stars, resembling our own Sun. By studying these remnants, scientists hope to shed light on the formation of stars, galaxies, and even fundamental elements.
This research was conducted by astrophysicist Stefania Salvadori from the University of Florence and her colleagues. The study’s findings were published on May 3rd in The Astrophysical Journal.
During the early stages of the universe, only simple elements like hydrogen and helium were present. The first stars ignited solely from these elements. Over time, their hot white cores gradually fused the simple atoms into heavier elements, such as carbon, oxygen, and magnesium, eventually leading to the formation of metals. Subsequent generations of stars were born from gas clouds containing these heavier atoms, and today, most observed stars are rich in metals like iron. Our Sun, for example, consists of approximately 98% hydrogen and helium but contains trace amounts of heavier elements like iron, neon, and carbon.
Directly observing the first metal-free stars in the universe is impossible since most of them have likely long since burned out and exploded. However, scientists can still study some remnants of their dusty remains by extending their gaze billions of light-years away.
Using the immense telescopic capabilities of the European Southern Observatory, Salvadori and her colleagues observed three gas clouds that gave birth to stars in the distant past. The gas clouds themselves didn’t reveal much to the scientists, but the light coming from nearby stellar standards (ultra-bright galactic core formed by matter falling into a supermassive black hole) helped unveil the secrets of these clouds. By analyzing the wavelengths of light absorbed by the gas clouds, the research team determined which elements were present in the composition of the remaining remnants of the stars.
According to the researchers, the clouds were extremely low in iron and other metal elements but rich in carbon, oxygen, and magnesium, which are the surviving remnants after the first stars depleted their fuel and exploded. These findings, along with other studies on the origins of stars, can help explain the composition of younger stars, including those found within our galaxy.
“Our discovery opens up new avenues for indirectly studying the nature of the first stars, complementing the extensive research on stars in our own galaxy,” said astrophysicist Stefania Salvadori.