  We present VLBI images of the RS CVn binary star HR 5110 (=BH CVn; HD
118216), obtained from observations made at 8.4 GHz on 1994 May 29/30 in
support of the NASA/Stanford Gravity Probe B project. Our images show an
emission region with a core-halo morphology. The core was 0.39 +/- 0.09 mas
(FWHM) in size, or 66% +/- 20% of the 0.6 +/- 0.1 mas diameter of the
chromospherically active K subgiant star in the binary system. The halo was
1.95 +/- 0.22 mas (FWHM) in size, or 1.8 +/- 0.2 times the 1.1 +/- 0.1 mas
separation of the centers of the K and F stars. The core increased
significantly in brightness over the course of the observations and seems to
have been the site of flare activity that generated an increase in the total
flux density of ~200% in 12 hours. The fractional circular polarization
simultaneously decreased from ~10% to 2.5%.
