Abstract
Application of digital cross-correlation spectroscopy to the spectra of the W Serpentis binaries SX Cas and RX Cas has allowed an accurate determination of the orbits and rotations of the (mass-losing) K-subgiant secondary components. The distortion of the primary radial-velocity curves due to the influence of the prominent accretion disks in these systems has been modelled to first order. This enables us to estimate k 1, and thereby the mass ratio q ≈ 0.30, to within ∼ ± 20%. The absolute radii of the secondaries are derived independently from the observed rotations and periods, assuming synchronous rotation. They show that the stars fill their Roche lobes, or at least very nearly so. Rough fits to the available photometry shows both primaries to be unevolved mid-B stars; that in RX Cas appears completely obscured by the disk. Preliminary spectroscopic data for W Ser and W Cru show some promise for similar analyses of these systems.
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Andersen, J.: 1973a, Publ. Astron. Soc. Pacific 85, 191
Andersen, J.: 1973b, in IAU Symp. No. 51, ed. A.H. Batten, Reidel, Dordrecht, p. 203
Andersen, J., Nordström, B., Mayor, M., Polidan, R. S.: 1988a, Astron. Astrophys., in press (Paper I)
Andersen, J., Pavlovski, K., Piirola, V.: 1988b, Astron. Astrophys., in press (Paper II)
Benz, W., Mayor, M.: 1981, Astron. Astrophys. 93, 235
Benz, W., Mayor, M.: 1984, Astron. Astrophys. 138, 183
Kalv, P.: 1979, Tartu Astron. Obs. Teated No. 58, 3
Koch, R. H.: 1972, Astron. J. 77, 500
Latham, D.W.: 1985, in IAU Colloq. No. 88, eds. A.G.D. Philip, D.W. Latham, L. Davis Press, Schenectady, N.Y., p. 21
Mayor, M.: 1985, in IAU Colloq. No. 88, eds. A.G.D. Philip, D.W. Latham, L. Davis Press, Schenectady, N.Y., p. 35
Pavlovski, K., Kříž, S.: 1985, Bull. Astron. Inst. Czech. 36, 153
Plavec, M.J.: 1980, in IAU Symp. No. 88, eds. M.J. Plavec, D.M. Popper, R.K. Ulrich, Reidel, Dordrecht, p. 251
Plavec, M.J., Weiland, J.L., Koch, R.M.: 1982, Astrophys. J. 256, 206
Shao, C.- Y.: 1967, Astron. J. 72, 480
Strupat, W.: 1987, Astron. Astrophys. 185, 150
Struve, O.: 1944a, Astrophys. J. 99, 89
Struve, O.: 1944b, Astrophys. J. 99, 295
Weiland, J.L., Plavec, M.J.: 1983, Bull. Am. Astron. Soc. 15, 916
Wilson, R.E., Devinney, E.J.: 1971, Astrophys. J. 166, 605
Wilson, R.E., Sofia, S.: 1976, Astrophys. J. 203, 182
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Andersen, J., Nordström, B. Fundamental parameters of the W Serpentis stars. Space Sci Rev 50, 179–189 (1989). https://doi.org/10.1007/BF00215929
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DOI: https://doi.org/10.1007/BF00215929