Astrophysics and Space Science

, Volume 152, Issue 2, pp 239–277 | Cite as

Photometry of the bright stars inside and outside associations in the spiral arm S5 of the andromeda galaxy

  • N. S. Nikolov
  • R. P. Tasheva
Article
  • 34 Downloads

Abstract

Photometry of more than 1000 bright stars of 20 associations and some fields in its vicinity is made, usingUBV plates taken with a 2-m Ritchey-Chrétien telescope of the National Observatory at the Bulgarian Academy of Sciences with limited magnitudes of about 20.6 inU andV, 21.6 inB. The colour-magnitudes of about 20.6 inU andV, 21.6 inB. The colour-magnitude and colour-colour diagrams of 12 associations and 8 fields are constructed and the brightest blue and red stars colour excesses, ages, and integrated luminosities of the associations are determined. The composite diagrams for all association and nonassociation measured stars are constructed too. Inside associations bright stars as well as non-stellar objects occur more often than outside. The brightest stars in S5 are withMv≃7 and do not differ considerably from the brightest ones in the spiral arm S4 of M31. Approximately the same are the absolute magnitudes of the brightest stars in our Galaxy and M33. A small difference between the brightest stars of the latter galaxy with those of M31 is possible because the stars in M33 are younger. This is in agreement with the concept that Sc galaxies (for example M33) are younger than Sb ones (for example M31). The same could be the reason for the smaller ratio of blue to red supergiants in M33 than in M31. The age estimations of the associations in S5 together with those in S4 in M31 show that they are older than the associations in M33 which is in agreement with the above mentioned concept.

Keywords

Small Difference Absolute Magnitude Small Ratio Bulgarian Academy Bright Star 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Baade, W. and Swope, H. H.: 1963,Astron. J. 68, 435.Google Scholar
  2. Curtev, R. G.: 1985, Master Degree Thesis, Univ. of Sofia.Google Scholar
  3. de Jager, C.: 1980,The Brightest Stars, D. Reidel Publ. Co., Dordrecht, Holland.Google Scholar
  4. de Vaucouleurs, G.: 1978,Astrophys. J. 223, 354.Google Scholar
  5. Efremov, Yu. N. and Ivanov, G. R.: 1987,Astrophys. Space Sci. 135, 210.Google Scholar
  6. Efremov, Yu. N., Ivanov, G. R., and Nikolov, N. S.: 1987,Astrophys. Space Sci. 135 119.Google Scholar
  7. Efremov, Yu. N.: 1978,Astron. Zh. Letters 4 125.Google Scholar
  8. Efremov, Yu. N.: 1979,Astron. Zh. Letters 5, 21.Google Scholar
  9. Efremov, Yu. N.: 1982,Astron. Zh. Letters 8, 585.Google Scholar
  10. Freedman, W. N.: 1984, Ph. D. Thesis, University of Toronto.Google Scholar
  11. Golev, V. K., Ivanov, G. R., and Kunchev, P. Z.: 1987,Astrophys. Space Sci. 135, 301.Google Scholar
  12. Hodge, P. V.: 1983,Astrophys. J. 264, 470.Google Scholar
  13. Hodge, P. V.: 1985, ‘Luminous Stars and Associations in Galaxies’, in C. de Loore, A. J. Willis, and P. Laskaradis (eds.),Astron. J. 116, 369.Google Scholar
  14. Hodge, P. W.: 1979,Astron. J. 84, 744.Google Scholar
  15. Humphreys, R. N.: 1979,Astrophys. J. 234, 854.Google Scholar
  16. Humphreys, R. M. and Sandage, A.: 1980,Astrophys. J. Suppl. 44, 319.Google Scholar
  17. Ivanov, G. R.: 1985,Astrophys. Space Sci. 110, 357.Google Scholar
  18. Ivanov, G. R. and Kunchev, P. Z.: 1985,Astron. Zh. Letters. 10, 737.Google Scholar
  19. Ivanov, G. R. and Kunchev, P. Z.: 1987,Compt. Rend. Bulg. Acad. Sci. 39, No. 12, 5.Google Scholar
  20. Kunchev, P. Z. and Nikolov, N. S.: 1986,Astrophys. Space Sci. 127, 327.Google Scholar
  21. Pellet, A., Astier, N., Viale, A., Courtes, G., Maucherat, A., Monnet, G., and Simien, F.: 1978,Astron. Astrophys. Suppl. 31, 439.Google Scholar
  22. Reddish, V. C.: 1962,Z. Astrophys. 56, 194.Google Scholar
  23. Sharov, A. S.: 1968,Astron. Zh. 45, 980.Google Scholar
  24. Tasheva, R. P. and Ivanov, G. R.:1986,Astron. Tsirk., No. 1426.Google Scholar
  25. van den Bergh, S.: 1964,Astrophys. J. Suppl. 9, 65.Google Scholar
  26. van den Bergh, S.: 1966,Astron. J. 71, 219.Google Scholar
  27. van den Bergh, S.: 1975, inStars and Stellar Systems, Vol. 9, p. 509.Google Scholar
  28. van den Bergh, S.: 1977,Décalages vers le rouge et l'expansion de l'Universe, p. 13.Google Scholar
  29. van Genderen, A. A.: 1973,Astron. Astrophys. 24, 47.Google Scholar
  30. Weigelt, G. and Baier, G.: 1985,Astron. Astrophys. 150, L18.Google Scholar
  31. Weigelt, G. and Ebersberger, J.: 1986,Astron. Astrophys. 163, L5.Google Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • N. S. Nikolov
    • 1
  • R. P. Tasheva
    • 1
  1. 1.Department of AstronomyUniversity of SofiaSofiaBulgaria

Personalised recommendations