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Annapurni Subramaniam |
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"Spectroscopic Survay of
Classical Be Stars in Northern Young Open Clusters" |
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Classical Be (CBe) stars in young open clusters are identified to study their properties as a function of age, spectral type and evolutionary stage. 207 northern open clusters were observed using slit-less spectroscopy method and 157 emission stars were identified in 42 clusters. Fraction of clusters housing CBe stars is maximum in both 0-10 and 20-30 Myr age bin (~40%). We find that the CBe phenomenon is unlikely due to core contraction near the turn-off, as these stars are located all along the main sequence. Rich clusters are found to favour early-type CBe stars. The distribution CBe stars show peaks at B1-B2 and B6-B7 spectral types. Our results indicate that there could be two mechanisms for CBe phenomenon: some are born as CBe stars and some become CBe stars during their MS life-time. |