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The Masses and Pulsation Modes of Classical Cepheids

Published online by Cambridge University Press:  12 April 2016

Arthur N. Cox*
Affiliation:
Theoretical Division, Los Alamos National Laboratory

Abstract

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Recent general observations pertaining to the masses and pulsation modes of classical Cepheids are reviewed. Certain special ones of these variables that display unusual behavior such as long term amplitude variations, overtone pulsations, and double-mode behavior, including one Cepheid in the first and second overtones as well as those in the fundamental and first overtone, are discussed in some detail. I suggest that the amplitude varying supergiant Cepheid HR 7308, which seems to be pulsating in the second radial overtone, is alternating between states where there is enough helium to barely give kappa and gamma effect driving, and where the helium has settled too deep for this driving. Reestablishment of the helium may be due to rapid levitation of the CNONe elements which cause convection and which then dredge-up the helium again to suppress the convection and also to drive pulsations. The use of Fourier fitting to the light and velocity curves have revealed some features that are interesting and are discussed, such as the pulsation mode discrimination and the derivation of accurate Wesselink radii. The seven methods of determining the masses of these stars are presented with a short critique of each. Evolution and pulsation masses depend on uncertain observed luminosities, and these have been revised recently. Evolution masses also depend on the blue looping yellow giant evolution tracks that may need revision because of convective core overshooting and possible opacity, Z, or Y abundance increases. The most discrepant masses, however, are those that depend on period ratios – the “bump” and “beat” masses. The possibility that the Cepheid internal structure can be modified enough by doubling the material opacity seems unlikely. It is suggested, though, that perhaps the period ratio mass anomaly solution can be found in CNONe element enhancement by radiation absorption levitation that would give higher opacities by abundance effects instead of any revisions in the opacity calculations. Some details for this mass anomaly “solution” are presented.

Type
1. Stellar Pulsation and Evolution
Copyright
Copyright © Cambridge University Press 1989

References

Andreasen, G.K. (1987). Astron. & Astrophys., 186, 159.Google Scholar
Andreasen, G.K. & Petersen, J.O. (1988). Astron. & Astrophys., 22, L4.Google Scholar
Antonello, E., Mantegazza, L. & Poretti, E. (1987). Lecture Notes in Physics, 274, 191.CrossRefGoogle Scholar
Arellano Ferro, A. (1983). Ap.J., 224, 755.CrossRefGoogle Scholar
Babel, J. & Burki, G. (1987). Astron. & Astrophys., 181, 34.Google Scholar
Barnes, T.G., Moffett, T.J., & Slovak, M.H. (1987). Ap.J.Suppl., 65, 307.Google Scholar
Barrell, S.L. (1981). M.N.R.A.S., 196, 357.Google Scholar
Becker, S.A. (1985). In Cepheids: Theory and Observations, ed. Madore, B.F., p. 104. Cambridge: Cambridge University Press.Google Scholar
Becker, S.A. & Cox, A.N. (1982). Ap.J., 260, 707.Google Scholar
Becker, S.A., Iben, I. & Tuggle, R.S. (BIT) (1977). Ap.J., 218, 633.Google Scholar
Böhm-Vitense, E. (1985). Ap.J., 296, 169.Google Scholar
Böhm-Vitense, E. (1986). Ap.J., 303, 262.Google Scholar
Böhm-Vitense, E. (1988). Ap.J.Lett., 324, L27.Google Scholar
Böhm-Vitense, E. & Proffitt, C. (1985). Ap.J., 296, 175.CrossRefGoogle Scholar
Breger, M. (1981). Ap.J., 249, 666.Google Scholar
Brunish, W.M. & Willson, L.A. (1987). Lecture Notes in Physics, 224, 27.Google Scholar
Burki, G. (1985). In Cepheids: Theory and Observations, ed. Madore, B.F., p. 34. Cambridge: Cambridge University Press.Google Scholar
Burki, G., Mayor, M. & Benz, W. (1982). Astron. & Astrophys., 109, 258.Google Scholar
Burki, G., Schmidt, E.G., Arellano Ferro, A., Fernie, J.D., Sasselov, D., Simon, N.R., Percy, J.R., & Szabados, L. (1986). Astron. & Astrophys., 168, 139.Google Scholar
Carson, T.R., Huebner, W.F., Magee, N.H., & Merts, A.L. (1984). Ap.J., 203, 466.CrossRefGoogle Scholar
Carson, T.R. & Stothers, R.B. (1988). Ap.J., 328, 196.CrossRefGoogle Scholar
Christy, R.F. (1968). Quart.J.R.A.S., 9, 13.Google Scholar
Cogan, B.C. (1970). Ap.J., 162, 139.CrossRefGoogle Scholar
Cogan, B.C., Cox, A.N., & King, D.S. (1980). Space Sci. Rev., 27, 419.Google Scholar
Cox, A.N. (1979). Ap.J., 229, 212.Google Scholar
Cox, A.N. (1980). Ann. Rev. Astron. Astrophys., 18, 15.Google Scholar
Cox, A.N., Deupree, R.G., King, D.S., & Hodson, S.W. (1977). Ap.J.Lett., 214, L127.Google Scholar
Cox, A.N. & Hodson, S.W. (1978). In The H-R Diagram, IAU Symposium 80, eds. Philip, A.G.D. & Hayes, D.S., p. 237. Dordrecht: Reidel.Google Scholar
Cox, A.N., Hodson, S.W. & King, D.S. (1979). Ap.J.Lett., 230, L109.CrossRefGoogle Scholar
Cox, A.N. & Kidman, R.B. (1984). In Observational Tests of the Stellar Evolution Theory, IAU Symposium 105, eds. Maeder, A. & Renzini, A.. Dordrecht: Reidel.Google Scholar
Cox, A.N., Michaud, G., & Hodson, S.W. (1978). Ap.J., 222, 621.Google Scholar
Cox, A.N. Tabor, J.E. (1976). Ap. J. Suppl., 31, 271.Google Scholar
Cox, J.P. (1980). Space Sci. Rev., 22, 389.Google Scholar
Deasy, H.P. (1988). M.N.R.A.S., 231, 673.Google Scholar
Deasy, H. & Butler, C.J. (1986). Nature, 320, 726.CrossRefGoogle Scholar
Demers, S. & Fernie, J.D. (1966). Ap.J., 144, 437.Google Scholar
Evans, N.R. & Arellano Ferro, A. (1987). Lecture Notes in Physics, 274, 183.Google Scholar
Evans, N.R. & Bolton, C.T. (1987). Lecture Notes in Physics, 274, 163.Google Scholar
Feast, M.J. & Walker, A.R. (1987). Ann. Rev. Astron. & Astrophys., 25, 345.Google Scholar
Fernie, J.D. (1984). In Observational Tests of the Stellar Evolution Theory, eds Maeder, A. & Renzini, A., p. 441. Reidel: Dordrecht.Google Scholar
Fernie, J.D. (1987a). Lecture Notes in Physics, 274, 167.Google Scholar
Fernie, J.D. (1987b). P.A.S.P., 99, 1093.Google Scholar
Fernie, J.D. & Chan, S.J. (1986). Ap.J., 303, 766.Google Scholar
Fricke, K., Stobie, R.S., & Strittmatter, P.A. (1972). Ap.J., 171, 593.Google Scholar
Gieren, W. (1976). Astron. & Astrophys., 47, 211.Google Scholar
Gieren, W. (1982). Ap.J., 260, 208.Google Scholar
Gieren, W. (1985). In Cepheids: Theory and Observations, ed. Madore, B.F., P. 98. Cambridge: Cambridge University Press.Google Scholar
Gieren, W.P. (1986a). Ap.J., 306, 25.Google Scholar
Gieren, W.P. (1986b). M.N.R.A.S., 222, 251.Google Scholar
Gieren, W.P. & Matthews, J.M. (1987). A. J., 94, 431.Google Scholar
Huang, R.Q. & Weigert, A. (1983). Astron. & Astrophys., 322, 309.Google Scholar
Iglesias, C.A., Rogers, F.J., & Wilson, B.G. (1987). Ap.J., 322, L45.CrossRefGoogle Scholar
Jacobsen, T.S. & Wallerstein, G. (1987). P.A.S.P., 99, 138.Google Scholar
Kidman, R.B. & Cox, A.N. (1985). In Cepheids: Theory and Observations, ed. Madore, B.F., p. 256. Cambridge: Cambridge University Press.Google Scholar
Magee, N.H., Merts, A.L., & Huebner, W.F. (1984). Ap.J., 283, 264.Google Scholar
Mantegazza, L. (1983). Astron. & Astrophys., 118, 321.Google Scholar
McAlary, C.W. & Welch, D.L. (1986). A.J., 91, 1209.CrossRefGoogle Scholar
Michaud, G., Vauclair, G., & Vauclair, S. (1983). Ap.J., 267, 256.CrossRefGoogle Scholar
Moffett, T.J. & Barnes, T.G. (1986). M.N.R.A.S., 219, 45p.Google Scholar
Moffett, T.J. & Barnes, T.G. (1987). Ap.J., 323, 280.CrossRefGoogle Scholar
Schmidt, E.G. (1984). Ap.J., 285, 501.CrossRefGoogle Scholar
Simon, N.R. (1982). Ap.J.Lett., 260, L87.Google Scholar
Simon, N.R. (1987). Lecture Notes in Physics, 274, 148.Google Scholar
Simon, N.R. & Aikawa, T. (1986). B.A.A.S., 17, 894.Google Scholar
Simon, N.R. & Lee, A.S. (1981). Ap.J., 248, 291.Google Scholar
Simon, N.R. & Moffett, T.J. (1985). P.A.S.P., 97, 1078.Google Scholar
Simon, N.R. & Schmidt, E.G. (1976). Ap.J., 205, 162.CrossRefGoogle Scholar
Stobie, R.S. (1969). M.N.R.A.S., 144, 485.CrossRefGoogle Scholar
Stobie, R.S. (1977). M.N.R.A.S., 180, 631.Google Scholar
Stothers, R. (1979). Ap.J., 229, 1023.Google Scholar
Teays, T.J. & Simon, N.R. (1985). Ap.J., 1290, 683.CrossRefGoogle Scholar
Turner, D.G. (1986). A.J., 92, 111.Google Scholar
Turner, D.G. & Evans, N.R. (1984). Ap.J., 283, 254.Google Scholar
Turner, D.G., Forbes, D.W., Lyons, R.W., & Havlen, R.J. (1985). In Cepheids: Theory and Observations, ed. Madore, B.F., p. 95. Cambridge: Cambridge University Press.Google Scholar
Welch, D.L., Evans, N.R., Lyons, R.W., Harris, H.C., Barnes, T.G., Slovak, M.H., & Moffett, T.J. (1987). P.A.S.P., 99, 610.Google Scholar
Woosley, S.E. & Phillips, M.M. (1988). Science, 240, 750.Google Scholar