Advertisement

Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Blue edges of the Delta-Scuti instability strip: Theory in comparison with observations

Abstract

Models of Delta Scuti stars are tested against radial pulsations in the four lowest modes, using a linear, nonadiabatic approximation. It is shown that the theoretical blue edge locations of the instability strip on the H-R diagram depend strongly (ΔlogT e≃0.03) on both opacity interpolation and variations of the envelope helium abundanceY. Several other factors have small effect (Δ logT e≲0.01): variations of the heavy element abundanceZ, the use of various opacity tables, the treatment of convection, and the number of envelope mass zones. A comparison with both results obtained by various authors and observations is performed. The locations of the observed blue edge and our theoretical third-harmonic ones are consistent. A nonlinear dependence of the theoretical blue edge locations on envelope helium abundanceY is derived. A star withY≃0.2 may pulsate within the instability strip, if it is not near the blue edge.

This is a preview of subscription content, log in to check access.

References

  1. Abraham, Z. and Iben, I.: 1971,Astrophys. J. 170, 157.

  2. Baglin, A., Breger, M., Chevalier, C., Hauck, B., le Contel, J. M., Sareyan, J. P., and Valtier, J. C.: 1973,Astron. Astrophys. 23, 221.

  3. Baker, N. H. and Gough, D. O.: 1979,Astrophys. J. 234, 232.

  4. Baker, N. and Kippenhahn, R.: 1965,Astrophys. J. 142, 868.

  5. Böhm-Vitense, E.: 1958,Z. Astrophys. 46, 108.

  6. Breger, M.: 1979,Publ. Astron. Soc. Pacific 91, 5.

  7. Breger, M. and Bregman, J. N.: 1975,Astrophys. J. 200, 343.

  8. Breger, M., Hsu, J. C., and Bozyan, E.: 1981,Inf. Bull. Var. Stars, No. 1966.

  9. Caputo, F., Castellani, V., and Tornambé, A.: 1980,Astron. Astrophys. 82, 79.

  10. Christy, R. F.: 1966a,Ann. Rev. Astron. Astrophys. 4, 353.

  11. Christy, R. F.: 1966b,Astrophys. J. 144, 108.

  12. Cox, A. N., King, D. S., and Hodson, S. W.: 1979,Astrophys. J. 228, 870.

  13. Cox, A. N., King, D. S., and Hodson, S. W.: 1980,Astrophys. J. 236, 219.

  14. Cox, A. N. and Stewart, J. N.: 1969,Sci. Inform. Astron. Council USSR Acad. Sci. 15, 3.

  15. Cox, A. N., King, D. S., and Tabor, J. E.: 1973,Astrophys. J. 184, 201.

  16. Cox, A. N. and Tabor, J. E.: 1976,Astrophys. J., Suppl. 31, 271.

  17. Deupree, R. G.: 1977,Astrophys. J. 214, 502.

  18. Deupree, R. G.: 1980,Astrophys. J. 236, 225.

  19. Iben, I.: 1971a,Astrophys. J. 166, 131.

  20. Iben, I.: 1971b,Publ. Astron. Soc. Pacific 83, 697.

  21. Iben, I. and Huchra, J.: 1971,Astron. Astrophys. 14, 293.

  22. Iben, I. and Tuggle, R. S.: 1972,Astrophys. J. 173, 135.

  23. Iben, I. and Tuggle, R. S.: 1975,Astrophys. J. 197, 39.

  24. Morton, D. C. and Adams, T. F.: 1968,Astrophys. J. 151, 611.

  25. Paczyński, B.: 1969,Acta Astron. 19, 1.

  26. Pamjatnykh, A. A.: 1974,Sci. Inform. Astron. Council USSR Acad. Sci. 31, 40.

  27. Pamjatnykh, A. A.: 1975a, Dissertation, Moscow.

  28. Pamjatnykh, A. A.: 1975b, in V. Sherwood and L. Plaut (eds.), ‘Variable Stars and Stellar Evolution’,IAU Symp. 67, 247.

  29. Pamjatnykh, A. A.: 1979,Sci. Inform. Astron. Council USSR Acad. Sci. 46, 126.

  30. Percy, J. R.: 1977,Monthly Notices Roy. Astron. Soc. 181, 563.

  31. Stellingwerf, R. F.: 1975,Astrophys. J. 195, 441.

  32. Stellingwerf, R. F.: 1979,Astrophys. J. 227, 935.

  33. Tsvetkov, Ts. G.: 1977a, Dissertation, Moscow.

  34. Tsvetkov, Ts. G.: 1977b,Sci. Inform. Astron. Council USSR Acad. Sci. 37, 63.

  35. Tsvetkov, Ts. G.: 1977c,Sci. Inform. Astron. Council USSR Acad. Sci. 37, 70.

  36. Tsvetkov, Ts. G.: 1981,Soviet Astron. J. (Astron. Zh.), in press.

  37. Tsvetkov, Ts. G.: 1982,Inf. Bull. Var. Stars, No. 2084.

  38. Tuggle, R. S. and Iben, I.: 1972,Astrophys. J. 178, 455.

  39. Valtier, J.-C., Baglin, A., and Auvergne, M.: 1979,Astron. Astrophys. 73, 329.

  40. van Albada, T. S. and Baker, N.: 1971,Astrophys. J. 169, 311.

  41. Vauclair, G.: 1976,Astron. Astrophys. 50, 435.

  42. Vauclair, G., Vauclair, S., and Pamjatnikh, A.: 1974,Astron. Astrophys. 31, 63.

  43. Vauclair, G., Vauclair, S., and Michaud, G.: 1978,Astrophys. J. 223, 920.

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Tsvetkov, T.G. Blue edges of the Delta-Scuti instability strip: Theory in comparison with observations. Astrophys Space Sci 89, 435–445 (1983). https://doi.org/10.1007/BF00655997

Download citation

Keywords

  • Convection
  • Helium
  • Heavy Element
  • Lower Mode
  • Nonlinear Dependence