Spectroscopic observations of massive stars (i.e., those more massive than 8 solar masses) allow astronomers to study their rapid evolution, which occurs on much shorter timescales compared to solar mass stars, and the impact of parameters such as stellar rotation on their evolution. To achieve this, observations of stellar clusters are greatly valuable, as they are groups of stars formed
The chemical history of Lithium abundance in the Universe is very complex. This chemical element has been first produced during the Big Bang, even if in very small quantities compared with hydrogen and helium. Since then, lithium is continuously created and destroyed by several processes occurring in stellar interior. This means that the lithium abundances we observe in stars today
