Optical spectroscopy of classical Be stars

We re-estimated the extinction parameter (A_V_) for our sample stars using the newly available data from Gaia DR2 and suggest that it is important to consider A_V_ while measuring the Balmer decrement (i.e. D_34_ and D_54_) values in classical Be stars. Subsequently, we estimated the Balmer decrement values for 105 program stars and found that ~20 per cent of them show D_34_>=2.7, implying that their circumstellar disc are generally optically thick in nature.

One program star, HD 60855 shows H{alpha} in absorption - indicative of disc-less phase. From our analysis, we found that in classical Be stars, H{alpha} emission equivalent width values are mostly lower than 40{AA}, which agrees with that present in literature. Moreover, we noticed that a threshold value of ~10{AA} of H{alpha} emission equivalent width is necessary for Fe II emission to become visible.