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Paper: |
Probing the Mass-Loss History of VY CMa |
Volume: |
378, Why Galaxies Care About AGB Stars: Their Importance as Actors and Probes |
Page: |
285 |
Authors: |
Decin, L.; Hony, S.; de Koter, A.; Justtanont, K.; Tielens, A.G.G.M.; Waters, L.B.F.M. |
Abstract: |
Mass loss plays a dominant role in the evolution of low-mass stars while they are on the Asymptotic Giant Branch (AGB). Recent studies have hinted towards the importance of time variability of the mass-loss rates of such objects. Likewise, more massive stars (MZAMS≥ 8M⊙) may pass through a red supergiant phase and lose mass in a similar manner. By modelling the full line profiles of low excitation CO transitions emitted in the circumstellar envelope (CSE), we have studied the mass-loss history of the well-studied supergiant VY CMa. We show that this source underwent a phase of high mass loss (~ 2.8× 10−4M⊙/yr) some 1000 yr ago. This phase lasted some 100 yr, and was followed by a low mass-loss phase (~ 1 × 10−6M⊙/yr) taking some 800 yr. The current mass-loss rate is estimated to be on the order of 1 × 10−4M⊙/yr. |
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