Abstract:
A sub-population (~9%) of hot (OB) stars exhibit strong (B~100-10,000
G), large-scale (often predominantly dipolar) magnetic fields that
channel their stellar wind outflows into circumstellar
magnetospheres. For young, rapidly rotating B-stars that have not yet
been spun down by wind-magnetic braking, wind material can be trapped
between the Kepler co-rotation radius (RK) and the Alfven radius (RA),
forming then a "Centrifugal Magnetosphere" (CM), with density set at
the critical level for "Centrifugal Breakout" (CBO) against the
confining magnetic tension. This talk discusses how such CBO controls
both the onset and strength of observed H-alpha emission, while the
energetics of the associated CBO-driven magnetic reconnection match
well the observed scalings of a non-thermal, circularly polarized
radio emission from such stars .
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