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Hi Steve,
A1 and B9 class stars are very close in temperature. Add the fact that the primary eclipse is only partial and the change in the continuum shape with temperature during eclipse will be very small.
From Ken's reference the range of RV is +-100km/s so the maximum shift from quadrature to eclipse (if total) would be 100km/s or 0.2nm at 600nm. Because the eclipse is partial though the shift in the line centre will be less than that. (There is a light curve in the paper so it would be possible to calculate the net contribution from each star during eclipse but I have not calculated it) This would be very tough to see with the Star Analyser due to the low resolution and difficulty in getting a high precision calibration. It is straightforward though with stable slit spectrographs to measure line centres to better than 1/10 of the resolution so the shift might be measurable with a resolution of say 0.5nm
Cheers
Robin
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