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Session 60 - Multiple Stars.
Display session, Wednesday, June 12
The radio corona of the binary system Algol was mapped at 8.4 and 15 GHz using the VLBA in April 1995. The observations used the nearby extragalactic source 0309+410 as a phase reference, allowing measurement of the source position to sub-mas precision. Snapshot maps were made every three hours over a nine hour total observation refenced to a common phase center. The source centroid moved \sim1 mas to the NE during the observation, consistent with the radio emission tracking the motion of the active KIV star. The overall source size at 8.4 GHz was 2.0 mas (1.4 K star diameters) or about twice the x-ray coronal size inferred from published eclipse observations. The observations suggest a model in which the radio and x-ray emission regions are centered on the K star, with the radio region overlaying the hotter thermal plasma.
Program listing for Wednesday