THE PARAMETERS OF B-EMISSION STARS ENVELOPE BASED ON THE LINE PROFILE OF H-ALPHA EMISSION

• Main Author: Evan Tri Asmono, Edoardus
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/35822
• Institution: Institut Teknologi Bandung

B-emission stars (Be) are stars with B class spectrum that has an emission line especially on the Hydrogen Balmer series that comes from stars envelope. The emission line that clearly visible is H? emission (6563Å) which is far from the star’s surface so it is slightly influenced by star activity. H? emission line profile can be either single peak or double peak (double peak phase and Be-shell phase). Be stars has rotation velocity (v sin i) which is close to its critical speed (70-80% vcrit). In this Final Project, 12 program stars were divided into 3 groups of phases : single peak phase, double peak phase, and Be-shell phase. H? emission line spectrums with double peak is used to determine the outer radius of the star envelope (Rd) by using the separation distance between the two peaks. Obtained the value of the outer radius of the star envelopes for 8 program stars ~1-17 R* and the value of Rd is proportional to v sin i. Relation between H? emission line parameters such as FWHM, W and V/R with Rd is not clear enough. FWHM has values comparable to v sin i and W. H? emission lines are dominated by weak emission lines, while the V/R ratio is dominated by V/R ~ 1. The V/R ratio does not have a relation with v sin i.