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Paper: Orbital Variations in the Spectroscopic Triple System 55 Ursae Majoris
Volume: 318, Spectroscopically and Spatially Resolving the Components of Close Binary Stars
Page: 248
Authors: Lehmann, H.; Hildebrandt, G.; Scholz, G.
Abstract: We investigate the radial velocities of the spectroscopic triple system 55 UMa. By combining our observations with earlier data from literature and by disentangling the radial velocity variations of close and wide orbit we get more accurate orbital solutions for all three components. Analysis shows that the close pair undergoes an apsidal advance of about 1° per year and that its orbital eccentricity decreased from 0.383 in 1954 to 0.316 in 2003. The rotational velocities of the components are different and exceed the synchronous rotational velocity. Both the high eccentricity and the fast rotation are in contradiction to those expected from the time scales of synchronization and circularization predicted for such a short-period binary.
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