| Abstract : | In the field of emission-line stars study, classical Be (CBe) star is one of the most distinctive classes of stars. One of the key features of CBe stars is its geometrically thin, equatorial, gaseous, decretion disc which is orbiting the star in Keplerian motion. The presence of the recombination emission lines and infrared excess in the spectra of CBe stars distinguish them from ordinary B-type stars. From literature, it has been established that the infrared excess in CBe stars is due to free-free emission (thermal bremsstrahlung) from the circumstellar disc. In this context, we will be studying the mid-infrared characteristics of CBe stars in order to evaluate the possibility of whether thermal bremsstrahlung is the primary explanation for the observed infrared excess. For this investigation, we are utilizing the benefit of all-sky WISE (Wide-field Infrared Survey Explorer) mid-infrared survey. We are taking two samples of Be stars from the Galaxy — one belonging to the field and the other from open clusters. As a follow-up, we will compare a sample of CBe stars belonging to diverse metallicity environments in the Galaxy and the Magellanic Clouds. This investigation of the infrared excess of CBe stars is to essentially explore the role of free-bound emission in addition to thermal bremsstrahlung and the distinct possibility of the dust formation in the disc; thus offering improved understanding regarding the disc nature in CBe stars. |
