Abstract Details
| Name: Mohana Thara C Affiliation: Christ University, Bangalore Conference ID: ASI2017_1252 Title : STUDY OF THE TRANSIENT NATURE OF Be STARS Authors and Co-Authors : Mohana Thara C (Christ University, Bengaluru), Dr.Paul K T (Christ University, Bangalore), Dr.Blesson Mathew (Tata Institute of Fundamental Research, Mumbai), Dr.Annapurni Subramaniam (Indian Institute of Astrophysics). Abstract Type : Poster Abstract Category : Stars,ISM and the Galaxy Abstract : We carried out a program to study the transient nature of circumstellar disc in classical Be stars using spectra collected over a period of three years with the Himalaya Faint Object Spectrograph Camera (HFOSC) mounted on the 2-m Himalayan Chandra Telescope (HCT). This is supplemented with the archival spectroscopic data from Be star spectra (BeSS) database. The formation of disc in classical Be stars, known as `Be phenomenon', is one of the unsolved problems in stellar research. By now it is clear how the material gets redistributed in the disc once it is launched from the star. However, the central problem of how material is launched from the star remains open. A way to tackle this problem is to estimate the disc formation and dissipation time scales in Be stars, particularly from the studies of a statistically large sample. A clever way to address this problem is through spectroscopy, wherein the profile changes of H-alpha give indication of the presence or absence of disc. In certain cases, Be stars were found to show H-alpha in absorption which is suggestive of a disc-loss episode. This is often followed by disc rebuilding phase, whose time scale is assessed from the recovery period of H-alpha to emission. We have identified a sample of ~20 Be stars going through Be -> B -> Be phase, from the cyclic variation of H-alpha from emission to absorption and back to emission. Never before disc-loss episodes were reported for such a large sample of Be stars. The implications of this result in understanding `Be phenomenon' will be discussed. |