Eta Virginis is a bright (V = 3.89) triple system of composite spectral type A2 IV that has been observed for over a dozen years with both spectroscopy and speckle interferometry. Analysis of the speckle observations results in a long period of 13.1 yr. This period is also detected in residuals from the spectroscopic observations of the 71.7919 day short-period orbit. Elements of the long-period orbit were determined separately using the observations of both techniques. The more accurate elements from the speckle solution have been assumed in a simultaneous spectroscopic determination of the short- and long-period orbital elements. The magnitude difference of the speckle components suggests that lines of the third star should be visible in the spectrum.
Hartkopf, W.I.; McAlister, H.A.; Yang, X.; Fekel, F.C. "Speckle and Spectroscopic Orbits of the Early A-Type Triple System in Virginis" Astronomical Journal v.103, p.1976 (1992)