Study of the Balmer decrements for Galactic classical Be stars using the Himalayan Chandra Telescope of India

In a recent study, Banerjee et al. (2021) produced an atlas of all major emission lines found in a large sample of 115 Galactic field Be stars using the 2-m Himalayan Chandra Telescope (HCT) facility located at Ladakh, India. This paper presents our further exploration of these stars to estimate the electron density in their discs. Our study using Balmer decrement values indicate that their discs are generally optically thick in nature with electron density (nₑ) in their circumstellar envelopes (CEs) being in excess of 10¹3 cm^-3 for around 65% of the stars. For another 19% stars, the average nₑ in their discs probably range between 10¹2 cm^-3 and 10¹3 cm^-3. We noticed that the nature of the H and Heta line profiles might not influence the observed Balmer decrement values (i. e. D₃4 and D₅4) of the sample of stars. Interestingly, we also found that around 50% of the Be stars displaying D₃4 greater than 2. 7 are of earlier spectral types, i. e. within B0 -B3.