Astrophysics and Space Science

, Volume 116, Issue 2, pp 355–365 | Cite as

CH Cygni in the transition to its cool phase

  • K. P. Panov
  • B. Kovachev
  • M. Ivanova
  • E. H. Geyer
Article
  • 18 Downloads

Abstract

U, B, V-observations, supplemented by spectrophotometric measurements of the symbiotic variable CH Cyg in the years 1982 to 1984 show that the star has reached its ‘blue maximum phase’ of its recent outburst in the first half of 1984. From end of July, 1984 on the object underwent a considerable drop in brightness and an increase of its colour indices, and which indicates that it was on the way to its cool phase. Also the spectroscopic observations show that the ‘blue’ continuum still observed at the beginning of July, 1984 has disappeared in October–November, 1984 and the strong absorption features, typical for a M-type giant were re-appearing. A remarkable intensity increase of the emission features, especially those of the Balmer lines, took place within this time interval. The rapid flickering variations of CH Cyg had also reached the culmination amplitude in July, 1984. There seem to be three periodicities present in these flickering variations with cycle lengths of 7.7 min, 21 min, and 60 min. Though these observational findings would be consistent with the M-type blue subdwarf component binary model with mass flow from the M6-III giant to the companion, the genuine binary nature of CH Cyg could not be established beyond doubt.

Keywords

Mass Flow Absorption Feature Strong Absorption Cycle Length Emission Feature 

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References

  1. Cester, B.: 1969,Astrophys. Space Sci. 3, 198.Google Scholar
  2. Deeming, T. J.: 1975,Astrophys. Space Sci. 36, 137.Google Scholar
  3. Deutsch, A. J.: 1967,IAU Circ., No. 2020.Google Scholar
  4. Faraggiana, R. and Hack, M.: 1971,Astron. Astrophys. 15, 55.Google Scholar
  5. Fehrenbach, C.: 1977,IAU Circ., No. 3102.Google Scholar
  6. Geyer, E. H.: 1981,Mitt Astrrn. Ges. 54, 228.Google Scholar
  7. Geyer, E. H. and Hänel, A.: 1982.ESO Messenger 29, 5.Google Scholar
  8. Hack, M., Rusconi, L., Engin, S., Sedmak, G., and Yilmaz, N.: 1982,Astron. Astrophys. 113, 250.Google Scholar
  9. Ichimura, K., Shimizu, Y., Nakagiri, M., and Yamashita, Y.: 1979,Tokyo Astron. Bull., 2nd series, No. 258.Google Scholar
  10. Johnson, H. M. and Golson, J.: 1969,Astrophys. J. 155, L91.Google Scholar
  11. Luud, L.: 1980,Astrofizika 16, 443.Google Scholar
  12. Luud, L., Tomov, T., Vennik, J., and Panov, K.: 1982,Pisma A.J. 8, 476.Google Scholar
  13. Martel-Chossat, M. T.: 1967,IAU Circ., No. 2027.Google Scholar
  14. Morris, S. C.: 1977,IAU Circ., No. 3101.Google Scholar
  15. Nakagiri, M. and Yamashita, Y.: 1982,Ann. Tokyo Astron. Obs 19, 1.Google Scholar
  16. Panov, K. P., Pamukchiev, I. Ch., Christov, P. P., Petkov D. I., Notev, P. T., and Kotsev, N. G.: 1982,Compt. Rend. Bulgarian Acad. Sci. 35, No. 6, 717.Google Scholar
  17. Persic, M., Hack, M., and Selvelli, P. L.: 1984,Astron. Astrophys. 140, 317.Google Scholar
  18. Reshetnikov, V. P. and Khudyakova, T. N.: 1984,Pisma A. J. 10, 673.Google Scholar
  19. Slovak, M. H. and Africano, J.: 1978,Monthly Notices Roy. Astron. Soc. 185, 591.Google Scholar
  20. Smith, S. E. and Bopp, B.: 1977,IAU Circ, No. 3113.Google Scholar
  21. Spiesman, W. J.: 1984,Monthly Notices Roy. Astron. Soc. 206, 77.Google Scholar
  22. Walker, G. A. H., Morris, S. C., and Younger, P. F.: 1969,Astrophys. J. 156, 117.Google Scholar
  23. Wallerstein, G.: 1968,Observatory 88, 111.Google Scholar
  24. Yamashita, Y. and Maehara, H.: 1979,Publ. Astron. Soc. Japan 31, 307.Google Scholar
  25. Yoo, K. H.: 1984,Ann. Tokyo Astron. Obs. 20, 2.Google Scholar
  26. Yoo, K. H. and Yamashita, Y.: 1982,Ann. Tokyo Astron. Obs. 19, 39.Google Scholar

Copyright information

© D. Reidel Publishing Company 1985

Authors and Affiliations

  • K. P. Panov
    • 1
  • B. Kovachev
    • 1
  • M. Ivanova
    • 1
  • E. H. Geyer
    • 2
  1. 1.Department of Astronomy and National Astronomical ObservatoryBulgarian Academy of SciencesSofiaBulgaria
  2. 2.Observatorium Hoher List d. Universitäts-Sternwarte BonnDaunGermany

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