Executive Summary : | Be stars, part of the emission line stars (ELs) category, are characterized by H-alpha emission lines in spectra, suggesting the presence of a circumstellar medium in the form of a disc. The formation of a decretion disc in a Classical Be star remains a mystery, but H-alpha emission can be transient, suggesting that the disc forms and dissipates in certain classical Be stars. The formation and evolution of discs in Be stars can be understood through the analysis of a population of Be stars in diverse metallicity environments. The LAMOsT survey program has provided data for stars from different regions of the Galaxy, particularly those in the anti-center direction. A sample of 3339 early-type ELs in the Galaxy was compiled, and a new population of classical Ae stars was found. The formation of discs in Be stars is mediated by the presence of a companion, which can be seen in the form of X-ray emission, known as Be or X-ray binaries. The researchers plan to analyze the role of binaries in a broader context and develop population models explaining the possible combination of companions to Be stars. They also aim to understand the formation of organic molecules in the protoplanetary disc of Herbig Ae or Be (HAeBe) stars. |