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Star Clusters in the Large Magellanic Cloud

  • Cesare Chiosi
Conference paper
Part of the Astrophysics and Space Science Library book series (ASSL, volume 162)

Abstract

In this paper, we discuss the main properties of the family of star clusters in the Large Magellanic Cloud (LMC). To this aim. we first review the stellar models for low and intermediate mass stars in occurrence of convective overshoot, and then describe an algorithm suitable for a theoretical approach to cluster photometry (colour magnitude (C-M) diagrams. luminosity functions (LF). integrated magnitudes and colours, and total masses). The Johnson BV CCD photometry of the stellar content of NGC 1866 is presented and used to test the theoretical models for intermediate mass stars with convective overshoot. The conclusion of this analysis is that these models fit the C-M diagram and LF of NGC 1866 much better than any other type of model in literature. In addition to this, the Johnson BV CCD photometry of NGC 3 831, another populous cluster of LMC somewhat older than NGC 3 866, is presented and analyzed by means of the same stellar models. In particular, we discuss the effect of unresolved binary stars on alleviating the discrepancy between the age determined from the main sequence stars and the age determined from the red giant stars. Following an idea advanced by Eggen and Iben (1988, 1989) to explain the existence of blue stragglers in young disk aggregates, we explore the possibility that delayed star formation has taken place in NGC 1831. The final part of the review deals with the integrated photometry of star clusters. Theoretical calibrations between integrated colours and age as a function of the chemical composition are briefly discussed. The aim is to derive the age distribution function of LMC cluster and interpret the physical cause of their bimodal distribution in (B-V). The main result is that bimodality simply originates from the kind of age distribution that LMC clusters happen to possess, whereas all other explanations put forward in literature play a marginal role. Furthermore, it is argued that the age distribution function show two peaks of major activity of cluster formation, whose ages are centered at about 1.5×10 and 2×10 yr ago. We also present new estimates of the total mass of many clusters derived from their integrated BV magnitudes. Finally a few words are addressed to the issue of the history of star formation in the field stars of LMC.

Keywords

Star Formation Main Sequence Star Cluster Luminosity Function Stellar Model 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Alongi, M., Chiosi, C.:1989a. Astrophys. J. submitted Alongi, M., Chiosi, C.:1989b. PreprintGoogle Scholar
  2. Arimoto, N., Yoshii, Y.:1986. Astron. Astrophys. 164, 260ADSGoogle Scholar
  3. Barbaro, G. : 1981. Astrophys. Sp. Sci. 77. 23ADSCrossRefGoogle Scholar
  4. Barbaro, G.:1982. Astrophys. Sp. Sci. 83, 143ADSCrossRefGoogle Scholar
  5. Barbaro, G., Bertelli, G.:1977. Astron. Astrophys. 54. 243ADSGoogle Scholar
  6. Becker, S.A.:1981. Astrophys. J. Suppl. 45, 478ADSCrossRefGoogle Scholar
  7. Becker, S. A., Iben, I Jr.:1979. Astrophys. J. 232. 831ADSCrossRefGoogle Scholar
  8. Becker, S. A., Mathews, G. J.:1983. Astrophys. J. 270, 155ADSCrossRefGoogle Scholar
  9. Bell, R. A., Gustafsson, B.:1978. Astron. Astrophys. Suppl. 34, 229ADSGoogle Scholar
  10. van den Bergh, S.:1981. Astron. Astrophys. Suppl. 46, 79ADSGoogle Scholar
  11. Bertelli, G., Bressan, A., Chiosi, C.:1985. Astron. Astrophys. 150. 33ADSGoogle Scholar
  12. Bertelli, G., Bressan, A., Chiosi, C., Angerer, K.:1986a. Astron. Astrophys. Suppl. Ser. 66, 191.ADSGoogle Scholar
  13. Bertelli, G., Bressan, A., Chiosi, C., Angerer, K.:1986b. In “The Age of Star Clusters”, ed. F. Caputo, Mem. Soc. Astron. It. 57.427.Google Scholar
  14. Boothroyd, A. I., Sackmann, I. J.:1988a. Astrophys. J. 328, 632.ADSCrossRefGoogle Scholar
  15. Boothroyd, A. I., Sackmann, I. J.:1988b. Astrophys. J. 328, 641.ADSCrossRefGoogle Scholar
  16. Boothroyd, A. I., Sackmann, I. J.:1988c. Astrophys. J. 328, 653.ADSCrossRefGoogle Scholar
  17. Boothroyd, A. I., Sackmann, I. J.:1988d. Astrophys. J. 328. 671.ADSCrossRefGoogle Scholar
  18. Bressan, A., Bertelli, G., Chiosi, C.:1981. Astron. Astrophys. 102, 25.ADSGoogle Scholar
  19. Bressan, A., Bertelli, G., Chiosi, C.:1986. In “The Age of Star Clusters”, ed. F. Caputo, Mem. Soc. Astron. It. 57, 411.Google Scholar
  20. Bruzual, A. G.1983. Astrophys. J. 273, 105ADSCrossRefGoogle Scholar
  21. Buonanno, R., Corsi, C. E., Fusi-Pecci, F.:1985. Astron. Astrophys. 145, 97ADSGoogle Scholar
  22. Burstein, D., Heiles, C.:1982. Astron. J. 87, 1365ADSCrossRefGoogle Scholar
  23. Buser, R., Kurucz, R. L.:1978. Astron. Astrophys. 70, 555ADSGoogle Scholar
  24. Castellani, V., Chieffi, A., Pulone, L., Tornambe’, A.:1985. Astron. Astrophys. 296, 204Google Scholar
  25. Chiosi, C.: 1986. In “Nucleosynthesis and Stellar Evolution”, 36th Saas-Fee Course, ed. B. Hauck et al., p. 199, Geneva ObservatoryGoogle Scholar
  26. Chiosi, C., Bertelli, G., Bressan, A.:1987. In “Late Stages of Stellar Evolution”. ed. S. Kwok and S. R. Pottasch, p. 239, Dordrecht: ReidelGoogle Scholar
  27. Chiosi, C., Bertelli, G., Bressan, A.:1988. Astron. Astrophys. 196, 84.ADSGoogle Scholar
  28. Chiosi, C., Bertelli, G., Meylan, G., Ortolani, S.:1989a. Astron. Astrophys. Suppl. Ser. 78, 89.ADSGoogle Scholar
  29. Chiosi, C., Bertelli, G., Meylan, G., Ortolani, S. (1989b). Astron. Astrophys. 219, 167.ADSGoogle Scholar
  30. Chiosi, C., Maeder, A.:1986. Ann. Rev. Astron. Astrophys. 24, 329.ADSCrossRefGoogle Scholar
  31. Chiosi, C., Matteuoci, F.: 1983. Astron. Astrophys. 105, 140.ADSGoogle Scholar
  32. Cohen, J G.:1982. Astrophys. J. 258, 143ADSCrossRefGoogle Scholar
  33. Da Costa, G. S., Mould, J., Crawford, M. D.:1984. Astrophys. J. 280, 595ADSCrossRefGoogle Scholar
  34. Eggen, O.J., Iben, I Jr.:1988. Astron. J. 96, 635ADSCrossRefGoogle Scholar
  35. Eggen, O.J., Iben, I Jr.:1989. Astron. J. 97, 431.ADSCrossRefGoogle Scholar
  36. Elson, R. A. W., Fall S. M.:1985. Astrophys. J. 299, 211.ADSCrossRefGoogle Scholar
  37. Frenk, C.S., Fall, S.M.:1982. Mon. Not. R. Astr. Soc. 199, 565.ADSGoogle Scholar
  38. Fusi-Pecci, F., Renzini, A.:1976. Astron. Astrophys. 46, 447.ADSGoogle Scholar
  39. Gascoigne, S. C. B.1980. In “Star Clusters”, ed. J. Hesser, p. 305. Dordrecht: ReideiGoogle Scholar
  40. Green, E. M., Demarque P., King, C. R.:1987. The Revised Yale Isochrones and Luminosity Functions Yale University, Observatory, New Haven.Google Scholar
  41. Gustafsson, B., Bell, R. A., Eriksson, K., Nordlund, A.1975. Astron. Astrophys. 42, 407ADSGoogle Scholar
  42. Hartwick F. D. A., Cowley, A.:1981. In “Astrophysical Parameters for Globular Clusters” eds. A. G. D. Philip & D. S. Hayes, L. Davis Press Inc., New York, p. 205.Google Scholar
  43. Heckman, T. M.:1976. Astrophys. J. Suppl. 36, 451.Google Scholar
  44. Iben, I Jr.:1975a. Astrophys. J. 196 525ADSCrossRefGoogle Scholar
  45. Iben, I Jr.:1975b. Astrophys. J. 196, 549.ADSCrossRefGoogle Scholar
  46. Iben, I Jr.:1976. Astrophys. J. 208. 165ADSCrossRefGoogle Scholar
  47. Iben, I Jr., Renzini, A.:1983. Ann. Rev. Astron. Astrophys. 21, 271.ADSCrossRefGoogle Scholar
  48. Lattanzio, J. C.:1986. Astrophys. J. 311. 708ADSCrossRefGoogle Scholar
  49. Lattanzio, J. C.:1987a. In “Lato Stages of Stellar Evolution”, ed. S. Kwok and S. R. Pottasch, p. 235, Dordrecht: Reidei.CrossRefGoogle Scholar
  50. Lattanzio, J. C.:1987b. Astrophys. J. Lett. 313, LI5ADSCrossRefGoogle Scholar
  51. Lattanzio, J. C.:1988a. In “Evolution of Peculiar Red Giant Stars”. In pressGoogle Scholar
  52. Lattanzio, J. C.:1988b. In “Origin and Distribution of the Elements”, ed. G. J. Mathews, p. 398, Singapore: World Scientific.Google Scholar
  53. Lattanzio, J.C.:1989. UCRL 100238 preprint.Google Scholar
  54. Maeder, A.:1974. Astron. Astrophys. 32, 177.ADSGoogle Scholar
  55. Maeder, A., Maynet, G.1989. Astron. Astrophys. 210, 155.ADSGoogle Scholar
  56. Mateo, M., Bertelli, G., Chiosi, C.:1989. Preprint.Google Scholar
  57. Mateo, M., Hodge, P.:1986a. Astrophys. J. 311, 113.ADSCrossRefGoogle Scholar
  58. Mateo, M., Hodge, P.:1986b. Astrophys. J. Suppl. 60. 893.ADSCrossRefGoogle Scholar
  59. Mateo, M., Hodge P. W.1987. Private Communication.Google Scholar
  60. Meylan, G.:1987a. Astron. Astrophys. 184, 144ADSGoogle Scholar
  61. Meylan, G.:1987b. In Stellar Evolution and Dynamics in the Outer Halo of the Galaxy, eds. M. Azzopardi, F. Matteucci, Garching, ESO, p. 665Google Scholar
  62. Meylan, G.:1988. Astron. Astrophys. 191, 215ADSGoogle Scholar
  63. Meylan, G., Djorgovski, S.1987. Astrophys. J. Lett. 322, L94.ADSCrossRefGoogle Scholar
  64. Persson, S. E., Aaronson, M., Cohen, J. G., Frogel, J. A., Matthews, K.:1983. Astrophys. J. 266, 105.ADSCrossRefGoogle Scholar
  65. Rabin, D.:1982. Astrophys. J. 261, 85ADSCrossRefGoogle Scholar
  66. Reimers, D.:1975. Mem. Soc. Roy. Sci. Liege 6 serie, tome 8, p. 369.ADSGoogle Scholar
  67. Renzini, A.:1981. Ann. Phys. Fr. 6, 87.ADSGoogle Scholar
  68. Renzini, A., Buzzoni, A.:1983. Mem. Soc. Astron. It. 54, 739.ADSGoogle Scholar
  69. Renzini, A., Buzzoni, A.:1986. In “Spectral Evolution of Galaxies”, ed. C. Chiosi, A. Renzini, p. 195. Dordrecht: Reidei.Google Scholar
  70. Salpeter, E. E.:1955. Astrophys. J. 121, 161ADSCrossRefGoogle Scholar
  71. Searle, L., Sargent, W. L. W., Bagnuolo, W. G.:1973. Astrophys. J. 179, 427ADSCrossRefGoogle Scholar
  72. Searle, L., Smith, H.1981. In “Astrophysicai Parameters for Globular Clusters”, eds. A. G. D. Philip and D. S. Hayes. L. Davis Press Inc., New York, p. 201.Google Scholar
  73. Searle, L., Wilkinson, A., Bagnuolo, W. G.:1980. Astrophys. J. 239, 803.ADSCrossRefGoogle Scholar
  74. Storm, J., Andersen, J., Blecha, A., Walker, M. F.:1988. Astron. Astrophys. 190. L18.ADSGoogle Scholar
  75. Vallenari, A., Chiosi, C., Bertelli, G., Meylan, G., Ortolani, S.: 1989. Astron. J. submitted.Google Scholar
  76. Walker, A. R.:1987. Mon. Not. R. Astr. Soc. 225, 627ADSGoogle Scholar
  77. Welch, D. L., McLaren, R. A., Madore, B. F., McAlary, C. W.:1987.Astrophys.J. 321, 162.ADSCrossRefGoogle Scholar
  78. Wielen, R.:1971. Astron. Astrophys. 13. 309.ADSGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Cesare Chiosi
    • 1
  1. 1.Department of AstronomyUniversity of PadovaItaly

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