Astrophysics and Space Science

, Volume 94, Issue 2, pp 295–305 | Cite as

Pi Gruis: Molecular identifications and spectral classification

  • P. S. Murty
Article

Abstract

Identifications of the molecular absorption features in the visible spectrum of the S star Pi Gruis are presented. Moderate dispersion spectrum of π1 Gru covering the region 5800–7300 Å, demonstrates the presence of a multitude of molecular bands. Wavelength measures of well over 150 red-degraded band heads are listed. Nearly 80% of the observed features are identified with the ZrO, LaO, YO, and CeO molecules. Many molecular bands due to ZrO, YO, and CeO are reported identified for the first time. Neither TiO molecular features nor any Ba compounds are detectable.

As a consequence of the presence of bands due tos-process oxides and the absence of TiO bands, π1 Gru may be classified as a pure S star. Observed predominance of the ZrO molecule suggests that both the phenomenon of Zr abundance enhancements and chemical equilibrium conditions with a carbon/oxygen ratio between 0.95 and 1.0 may be at play in the atmospheres of cooler pure S stars.

Keywords

Chemical Equilibrium Condition Absorption Feature Molecular Feature Chemical Equilibrium Visible Spectrum 

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References

  1. Afaf, M.: 1950a,Proc. Phys. Soc. 63A, 674.Google Scholar
  2. Afaf, M.: 1950b,Proc. Phys. Soc. A63, 1156.Google Scholar
  3. Ake, T. B.: 1979,Astrophys. J. 234, 538.Google Scholar
  4. Akerlind, L.: 1956,Arkiv Fysik 11, 396.Google Scholar
  5. Akerlind, L.: 1962,Arkiv Fysik 22, 65.Google Scholar
  6. Balfour, W. J. and Tatum, J. B.: 1973,J. Mol. Spectrosc. 48, 313.Google Scholar
  7. Barrow, R. F., Clements, R. M., Harris, S. M., and Jenson, P. P.: 1979,Astrophys. J. 229, 439.Google Scholar
  8. Bernard, A., Bacis, R., and Luc, P.: 1979,Astrophys. J. 227, 338.Google Scholar
  9. Bernard, A. and Gravina, R.: 1980,Astrophys. J. Suppl. 44, 223.Google Scholar
  10. Boesgaard, A. M.: 1970,Astrophys. J. 161, 163.Google Scholar
  11. Boeshaar, P. C. and Keenan, P. C.: 1979,Richerche Astronomiche 9, 39.Google Scholar
  12. Clegg, R. E. S. and Lambert, D. L.: 1978,Astrophys. J. 226, 931.Google Scholar
  13. Davis, D. N.: 1971,Astrophysics 167, 327.Google Scholar
  14. Dubois, I.: 1977,Astron. Astrophys. 57, 51.Google Scholar
  15. Feast, M. W.: 1953,Monthly Notices Roy. Astron. Soc. 113, 510.Google Scholar
  16. Feast, M. W., Catchpole, R. M., and Glass, I. S.: 1976,Monthly Notices Roy. Astron. Soc. 174, 81.Google Scholar
  17. Gatterer, A., Junkes, J., Salpeter, E. W. and Rosen, B.: 1957,Molecular Spectra of Metallic Oxides, Specola Vaticana, Vatican City.Google Scholar
  18. Huber, K. P. and Herzberg, G.: 1979,Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules, Van Nostrand Reinhold, New York.Google Scholar
  19. Keenan, P. C.: 1950,Astron. J. 55, 74.Google Scholar
  20. Keenan, P. C.: 1954,Astrophys. J. 120, 484.Google Scholar
  21. Keenan, P. C.: 1957,Publ. Astron. Soc. Pacific 69, 5.Google Scholar
  22. Keenan, P. C.: 1966,Astrophys. J. Suppl. 13, 333.Google Scholar
  23. Keenan, P. C. and Boeshaar, P. C.: 1980,Astrophys. J. Suppl. 43, 379.Google Scholar
  24. Keenan, P. C. and McNeil, R. C.: 1976,An Atlas of Spectra of the Cooler Stars, The Ohio State University Press, Columbus, Ohio.Google Scholar
  25. Lagerquist, A., Uhler, U., and Barrow, R. F.: 1954,Arkiv Fysik 8, 281.Google Scholar
  26. Lambert, D. L. and Clegg, R. E. S.: 1980,Monthly Notices Roy. Astron. Soc. 191, 367.Google Scholar
  27. Lauchlan, L. J., Brom, J. M., Jr., and Broida, H. P.: 1976,J. Chem. Phys. 65, 2672.Google Scholar
  28. Lindgren, B.: 1973,J. Mol. Spectrosc. 48, 322.Google Scholar
  29. Lindgren, B. and Olofsson, G.: 1980,Astron. Astrophys. 87, 300.Google Scholar
  30. Linton, C., Dulick, M., and Field, R. W.: 1979,J. Mol. Spectrosc. 78, 428.Google Scholar
  31. Linton, C., Dulick, M., Field, R. W., Carette, P., and Barrow, R. F.: 1981,J. Chem. Phys. 74, 189.Google Scholar
  32. Lowater, F.: 1932,Proc. Phys. Soc. 44, 51.Google Scholar
  33. Merrill, P. W.: 1922,Astrophys. J. 56, 457.Google Scholar
  34. Merrill, P. W.: 1952,Astrophys. J. 116, 21.Google Scholar
  35. Merrill, P. W. and Greenstein, J. L.: 1956,Astrophys. J. Suppl. 2, 225.Google Scholar
  36. Moore, C. E., Minnaert, M. G. J., and Houtgast, J.: 1966,The Solar Spectrum 2935 to 8770 Å, Government Printing Office, Washington.Google Scholar
  37. Murty, P. S.: 1980a,Astrophys. J. 240, 363.Google Scholar
  38. Murty, P. S.: 1980b,Astrophys. J. 240, 585.Google Scholar
  39. Murty, P. S.: 1980c,Astrophys. Space Sci. 68, 513.Google Scholar
  40. Murty, P. S.: 1982,Astrophys. Letters 23, 7.Google Scholar
  41. Murty, P. S.: 1983,Astrophys. Letters 23, 77.Google Scholar
  42. Nassau, J. J. and van Albada, G. B.: 1948,Astrophys. J. 107, 418.Google Scholar
  43. Peery, B. F., Jr.: 1971,Publ. Astron. Soc. Pacific 83, 162.Google Scholar
  44. Peery, B. F., Jr.: 1979,Publ. Astron. Soc. Japan 31, 461.Google Scholar
  45. Phillips, J. G. and Davis, S. P.: 1976a,Astrophys. J. 206, 632.Google Scholar
  46. Phillips, J. G. and Davis, S. P.: 1976b,Astrophys. J. Suppl. 32, 537.Google Scholar
  47. Phillips, J. G. and Davis, S. P.: 1979,Astrophys. J. 229, 867.Google Scholar
  48. Phillips, J. G., Davis, S. P., and Galehouse, D. C.: 1979,Astrophys. J. 234, 401.Google Scholar
  49. Piccirillo, J.: 1980,Monthly Notices Roy. Astron. Soc. 190, 441.Google Scholar
  50. Rosen, B.: 1970,Seleced Constants — Spectroscopic Data Relative to Diatomic Molecules, Pergamon Press, London.Google Scholar
  51. Scalo, J. M. and Ross, J. E.: 1976,Astron. Astrophys. 48, 219.Google Scholar
  52. Shin, J. B. and Nicholls, R. W.: 1977,Spectrosc. Letters 10, 923.Google Scholar
  53. Stephenson, C. B.: 1976, ‘A General Catalogue of S Stars’,Publ. Warner and Swasey Obs. 2, No. 2.Google Scholar
  54. Tatum, J. B. and Balfour, W. J.: 1973,J. Mol. Spectrosc. 48, 292.Google Scholar
  55. Truran, J. and Iben, I.: 1977,Astrophys. J. 216, 797.Google Scholar
  56. Tsuji, T.: 1971,Publ. Astron. Soc. Japan 23, 275.Google Scholar
  57. Uhler, U.: 1954,Arkiv Fysik 8, 295.Google Scholar
  58. Uhler, U. and Akerlind, L.: 1956,Arkiv Fysik 10, 431.Google Scholar
  59. Wing, R. F.: 1972,Mem. Soc. Roy. Sci. Liège 3, 123.Google Scholar
  60. Wing, R. F. and Yorka, S. B.: 1977,Monthly Notices Roy. Astron. Soc. 178, 383.Google Scholar
  61. Wyckoff, S. and Clegg, R. E. S.: 1978,Monthly Notices Roy. Astron. Soc. 184, 127.Google Scholar
  62. Wyckoff, S. and Wehinger, P. A.: 1976,Mem. Soc. Roy. Sci. Liège 9, 445.Google Scholar
  63. Wyckoff, S. and Wehinger, P. A.: 1977,Astrophys. J. 212, L139.Google Scholar
  64. Wyckoff, S., Wehinger, P. A., and Clegg, R. E. S.: 1978,Mem. Soc. Roy. Sci. Liège 10, 215.Google Scholar
  65. Yamashita, Y.: 1973,Publ. Astron. Soc. Japan 25, 511.Google Scholar

Copyright information

© D. Reidel Publishing Co 1983

Authors and Affiliations

  • P. S. Murty
    • 1
  1. 1.Indian Institute of AstrophysicsKodaikanalIndia

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