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Paper: An Abundance Analysis of Pulsating and Non-Pulsating Subluminous B Stars: Preliminary Results
Volume: 392, Hot Subdwarf Stars and Related Objects
Page: 123
Authors: Pereira, C.; Jeffery, C.S.
Abstract: Extreme horizontal branch stars show both short and long period oscillations, identified as p-mode and g-mode oscillations respectively. Both are thought to be driven by the iron opacity bump also known as the κ-mechanism. However, not all sdBs lying within the predicted p-mode instability region show pulsations. Thus, the coexistence of pulsating and non-pulsating sdBs sharing similar spectroscopic properties is an interesting question that needs to be addressed. Proposed solutions include (a) weak stellar winds depleting the iron reservoir needed to drive the oscillations and (b) perturbation of the driving region due to the rapid movement of the material within the star during the oscillations. As a first approach, we investigate surface abundances in a sample of variable and non-variable B subdwarfs to establish whether significant differences exist between the two groups.
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