Astronomers have discovered a huge debris flow of old stars at the southern edge of the Milky Way.
The orbits of these giant streams of stars range from 20,000 light-years at their closest approach to the center of the Milky Way to 90,000 light-years at their furthest distance. If this stream of stars were visible in the night sky, it would appear 30 times larger than the full moon!
Just a little bit of metal
Known as C-19, this stream of stars is the remnant of an ancient globular cluster. The globular cluster is a group of old stars. That means these stars have burned out hydrogen and helium and are dominated by heavy elements.
Interestingly, stellar currents are low in metals or heavy elements. Based on observational results and developed theories, the heavy elements in the globular cluster should not be less than 0.2%. However, the abundance of heavy metals or elements at C-19 is only 0.05% or 4 times lower than that of globular clusters observed in and around the Milky Way.
Based on existing theory, star clusters with few heavy elements should have disappeared a long time ago. There is even a theory that states that such a cluster cannot arise at all.
From the beginning of the universe
The discovery of stellar streams with low metal abundances clearly had implications for the formation of stars, star clusters, and galaxies when the Universe was young. The existence of this star stream is evidence that the globular cluster and the material that formed the Milky Way formed in a metal-sparse environment. That means this globular cluster formed before the next generation of stars produced heavier elements for the universe.
In short, C-19 observed with the Gemini North telescope was formed when the universe was young and the first stars were forming in the universe.
What can we get from C-19?
This very old C-19 could be a source of information about the formation of stars and star clusters after the Big Bang. Even more interesting is that this C-19 cluster is relatively close to Earth, or more specifically, close to the Milky Way. In this way we can study the structure of old galaxies in our cosmic environment.
According to Julio Navarro of the University of Victoria: “While astronomers knew they could search distant galaxies to study the universe, we now also know that we can study the oldest structures in our galaxy as fossils from ancient times.
Although stars contain chemical elements on the periodic table, the main composition of stars is hydrogen and helium. The astronomer Cecilia Payne-Gaposchkin (1900-1979) was the first to put forward this idea in 1925. However, this idea was scrapped until the idea was later proven to be true through conducted research. Cecilia later became the first female professor at Harvard University.