Study: Revealing the evolution of the Milky Way through data from Chinese and European telescopes
BEIJING, March 25, 2022 (Xinhua) Astronomers have made an accurate map of how our galaxy, the Milky Way, formed and evolved in the beginning and emerging stages, using space survey data obtained by the Multi-Object Fiber Spectroscopic Telescope (LAMOST) in China, and the satellite (Gaia) of the European Space Agency.
The study was published last Thursday in the journal (Nature) as a main story for the cover of the magazine, as the study included an analysis of about 250 thousand giant stars with very accurate ages, noting that the formation of the ancient thick disk of the galaxy began about 13 billion years ago, that is, after only 800 million years. From the history of the cosmic big bang.
Chiang Maosheng and Hans Walter Rex of the Max Planck Institute for Astronomy analyzed millions of spectra of stars monitored by Lamost, as well as the positions and motions of 1.4 billion stars monitored by the Gaia satellite.
The results showed that the evolution of the galaxy can be divided into two parts: the early stage from 13 billion years ago to 8 billion years ago, when the stellar halo and the thick disk formed, and the later stage when the thin disk formed.
Most of those stars formed in a thick disk about 11 billion years ago, when Gaia Susig, the remnant of a dwarf galaxy, merged with our own, adding at least eight globular clusters along with 50 billion solar masses of stars, gas and dark matter.
Over the five to six billion years after that date, the galaxy experienced a continuous enrichment of chemical elements, eventually reaching a factor of 10, while the star-forming gas managed to remain in a good mixed state, according to the study.
The researchers said that the age, composition and movement of these stars have shed light on the dynamic processes that interacted to form our galaxy.