Astronomers at the Harvard-Smithsonian Center for Astrophysics in Cambridge have discovered a very old star, which could be part of the second generation of stars that formed after the Big Bang. Baptized asS1020549, is located in thedwarf galaxySculptor, 280,000 light-years away, and hasa chemical composition very similar to the oldest stars in the Milky Way. Their composition supports the theory that our galaxy went through a “cannibal” phase, growing to its current size by “devouring” dwarf galaxies.
Applying a new method developed by scientists from the Carnegie group of observatories (United States), it has been calculated that the now discovered star hasan amount of metal more than 4,000 times less than that of the Sun-five times less than any other star found before in a dwarf galaxy-, so Anna Frebel, the main author of the work, has stated that probablyit is “almost as old as the universe itself”. Since they are the product of stellar evolution, metals were rare in the early Universe.
In addition, an analysis of the levels ofiron, magnesium, calcium and titaniumfromS1020549 has allowed researchers to show that the proportions resemble those of the oldest stars in the Milky Way, providing the first observational support for the idea that these stars originally formed in dwarf galaxies.
Astronomers hope that further studies will reveal more metal-poor stars, although the distance and weakness of these stars pose a real challenge to the optics of current telescopes. The next generation, which will include among others the Large Magellan Telescope of 24.5 meters, will open a new window to the study of thegalaxy chemistry.
