Published
23/03/2026 às 13:15
An extremely old star identified within the dwarf galaxy Pictor II may help astronomers shed light on a central question about the origin of the ingredients of life in the universe. Captured in an image obtained by the Dark Energy Camera (DECam) at the Víctor M. Blanco Telescope in Chile, the star PicII-503 stands out for its unusual composition.
The photograph shows a bright star field within Pictor II, a dwarf galaxy over 10 billion years old. At the center of scientific interest is PicII-503, described as a Population II star, also called a second-generation star.
Ancient star preserved in primordial galaxy
Population II stars formed when the cosmos was still young and heavier elements were scarce. Therefore, they are composed primarily of hydrogen and helium, with very small amounts of metals compared to more recent stars.
In the case of PicII-503, this characteristic appears in an extreme form. According to the data presented, it has approximately only 1/40.000th of the iron found in the Sun, which is much younger.
Excess carbon attracts the attention of astronomers.
Although it has little iron, the star has a very high abundance of carbon. Researchers reported that the carbon-to-iron ratio in PicII-503 is more than 1.500 times higher than that observed in the Sun.
This pattern also appears in many other Population II stars. However, scientists have faced difficulties in confirming the proposed explanations for this phenomenon because several of these stars had already moved away from their original locations when they were detected.
Star composition helps test theories.
PicII-503’s situation is different because it remains within its primordial dwarf galaxy. This has allowed astronomers to act as “stellar archaeologists,” analyzing its composition to test hypotheses about the formation and dispersal of elements in the universe.
The carbon-rich composition reinforces the idea that, during the supernova explosion that marks the end of a star’s life, the carbon present in the outer layers can be launched to greater distances than other elements. This dynamic would help explain why carbon has spread so widely throughout the universe.
The importance of this result goes beyond the description of a rare star. Since carbon is identified as an element particularly suited to act as a primary component of life, the observation of PicII-503 offers a concrete clue as to how this material may have been distributed throughout the cosmos since its earliest periods.