Abstract Details

Name: Ranjani.L.Kandi
Affiliation: Christ University,Bangalore
Conference ID: ASI2016_442
Title : Long term variability of Hα emission line profiles in selected Be-Stars
Authors and Co-Authors : (2) K T Paul, Christ University, Hosur Road, Bangalore 560029,paul.kt@christuniversity.in (3)Annapurni Subhramaniam, Indian Institute of Astrophysics, Bangalore 560034,purni@iiap.res.in (4)Shruthi Bhat ChristUniversity,Hosur Road, Bangalore560029, shruthibhat89@gmail.com
Abstract Type : Poster
Abstract Category : Stars, The Milky Way Galaxy and its neighbours
Abstract : A Be star is a non-super-giant B type star whose spectrum has, or had at some time, one or more Balmer lines in emission. It is widely accepted that Be stars are rapidly rotating stars surrounded by disks or ring-like envelopes in the equatorial region, where the emission lines are formed. These disks are formed due to the decretion of mass from the central star. Investigation of Hα emission line reveals important information about the circumstellar disk parameters and their variability over a period of time. The Be-phenomenon or the B <-> Be phase is not yet understood very clearly. Long term and gradual variations of the circumstellar emission & absorption lines are common to all Be stars. In addition, there is also more rapid (short-term) variability observable both in photometry and spectroscopy. The most common emission line profile seen for the Be stars is the double-peaked Hα line. For these type of profiles, V/R variations are the most common type of variability. The V/R variations are said to be periodic on a long term basis. We present a set ofspectroscopic study of 25 program stars of double peaked emission line profile, available in the BeSS database. This database contains the complete catalog of classical Be stars and Herbig Ae/Be-stars, and assembles spectra. The required spectroscopic parameters such as EW, FWHM, V/R will be obtained for each of the stars, using which the disk radius will be calculated in terms of the stellar radius. The period of long term variability will also be determined and correlations between the spectroscopic parameters will be established.