Our galaxy is made up of several parts, primarily a disk and a halo, a spherical region around the disk. The disc, in turn, consists of a thick disc and a thin one. Most of the stars visible in the sky belong to a thin disk, a thick disk is twice the height of a thin one, but has a smaller radius.
Maoshen Xiang from the German Institute of Astronomy. Max Planck and his colleagues analyzed data from the Gaia space observatory on the brightness and position of stars. To these data, they added information regarding the chemical composition of stars obtained by the Chinese telescope LAMOST. The researchers focused their attention on subgiants – stars in which thermonuclear reactions stopped in the core and began in the shell. This stage of the existence of a star is very short, and allows you to accurately determine its age.
It turned out that the thick disk began to form 13 billion years ago, two billion years earlier than thought and 0.8 billion years following the Big Bang. These data will allow us to build a more accurate model of the formation of our galaxy and explore the early history of the universe.
