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The moon and the planets

, Volume 18, Issue 3, pp 343–359 | Cite as

Cometary brightness variation and nucleus structure

  • Fred L. Whipple
Article

Abstract

The Bobrovnikoff and Beyer photometric data for more than 100 comets have been analyzed for intrinsic brightness variations,before andafter perihelion, according to ther−n law, wherer is solar distance. The Oort and Schmidt classification of comet ‘age’ has been extended and applied with Marsden's new determinations of inverse semi-major axis, 1/a, original. All classes of comets withP>25 yr show statistically the same value ofn after perihelion. New comets approach perihelion with smaller values ofn and older comets with increasingly larger values (Table II). For comets ofP<25 yr,n is larger and erratic.

A physical interpretation involves the quick loss of a frosting of super-volatile materials from new comets; then, for all comets, the development of an insulating crust after perihelion. The crust also includes ‘globs’ of meteoroidal and icy material. The crust tends to be purged near perihelion but generally to grow in a spotty fashion with cometary age. The orientation of the axes of rotating comets is shown to be an important unknown factor in cometary brightness variations. A speculation is made concerning the axis of rotation for C/Kohoutek, 1973 XII.

Keywords

Physical Interpretation Unknown Factor Brightness Variation Photometric Data Nucleus Structure 
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. Alfvén, H. and Arrhenius, G.: 1976,NASA SP-345, Ch. 19.Google Scholar
  2. Beyer, M.: 1933,Astron. Nachr. 250, 232.Google Scholar
  3. Beyer, M.: 1937,Astron. Nachr. 262, 223.Google Scholar
  4. Beyer, M.: III, 1938,Astron. Nachr. 264, 401.Google Scholar
  5. Beyer, M.: IV, 1938,Astron. Nachr. 265, 37.Google Scholar
  6. Beyer, M.: V, 1942,Astron. Nachr. 272, 249.Google Scholar
  7. Beyer, M.: VI, 1948,Astron. Nachr. 275, 237.Google Scholar
  8. Beyer, M.: VII, 1950,Astron. Nachr. 278, 217.Google Scholar
  9. Beyer, M.: IX, 1955,Astron. Nachr. 282, 145.Google Scholar
  10. Beyer, M.: X, 1958,Astron. Nachr. 284, 112.Google Scholar
  11. Beyer, M.: XI, 1959,Astron. Nachr. 284, 241.Google Scholar
  12. Beyer, M.: XII, 1962,Astron. Nachr. 286, 219.Google Scholar
  13. Beyer, M.: XIII, 1963,Astron. Nachr. 287, 153.Google Scholar
  14. Beyer, M.: XIV, 1964,Astron. Nachr. 288, 113.Google Scholar
  15. Beyer, M.: XV, 1966,Astron. Nachr. 289, 173.Google Scholar
  16. Beyer, M.: XVI, 1969,Astron. Nachr. 291, 239.Google Scholar
  17. Beyer, M.: XVII, 1972,Astron. Nachr. 293, 241.Google Scholar
  18. Beyer, M.: 1969,Astron. Nachr. 291, 257.Google Scholar
  19. Bobrovnikoff, N. T.: 1942,Cont. Perkins Obs. No. 16, 190.Google Scholar
  20. Ceplecha, Z. and McCrosky, R. E.: 1976,J. Geophys. Res. 81, 6257.Google Scholar
  21. Delsemme, A. H. and Rud, D. A.: 1973,Astron. Astrophys. 28, 1.Google Scholar
  22. Delsemme, A. H. and Wenger, A.: 1970,Planet. Space Sci. 18, 709.Google Scholar
  23. Donn, B.: 1976,NASA SP-393, 611.Google Scholar
  24. Everhart, E.: 1968,Astron. J. 73, 1039.Google Scholar
  25. Everhart, E.: 1972,Astrophys. Letters 10, 131.Google Scholar
  26. Fay, T. D. and Wisniewski, W.: 1976, Preprint, Lunar Planetary Laboratory, Tucson, Arizona.Google Scholar
  27. Fayet, M.: 1910,Ann. Paris, Mem. 26A.Google Scholar
  28. Hruška, A. and Vanýsek, V.: 1958,Astron. Inst. Czech. Acad. Sci., Pub. No. 41, 1.Google Scholar
  29. Kresák, L.: 1973,Bull. Astron. Inst. Czech. 24, 264.Google Scholar
  30. Levin, B.: 1948,Astron. Zh. 20, 48.Google Scholar
  31. Marsden, B. G.: 1975,Catalogue of Cometary Orbits (2nd edn), Smithsonian Astrophysical Observatory, Cambridge, Mass.Google Scholar
  32. Marsden, B. G. and Sekanina, Z.: 1973,Astron. J. 78, 1118.Google Scholar
  33. Meisel, D. D. and Morris, C. S.: 1976,NASA SP-393, 410.Google Scholar
  34. O'Dell, C. R.: 1976,Pub. Astron. Soc. Pac. 88, 342.Google Scholar
  35. Oort, J. H.: 1950,Bull. Astron. Neth. 11, 91.Google Scholar
  36. Oort, J. H. and Schmidt, M.: 1950,Bull. Astron. Neth. 11, 259.Google Scholar
  37. Schmidt, M.: 1950,Bull. Astron. Neth. 11, 253.Google Scholar
  38. Van Woerkom, A. J. J.: 1948,Bull. Astron. Neth. 10, 445.Google Scholar
  39. Whipple, F. L.: 1940,Proc. Am. Phil. Soc. 83, 84.Google Scholar
  40. Whipple, F. L.: 1950,Astron. J. 111, 375.Google Scholar
  41. Whipple, F. L.: 1951,Astron. J. 113, 464.Google Scholar
  42. Whipple, F. L.: 1976,Proc. IAU Colloq. No. 39, Lyon, France (in press).Google Scholar

Copyright information

© D. Reidel Publishing Company 1978

Authors and Affiliations

  • Fred L. Whipple
    • 1
  1. 1.Center for AstrophysicsSmithsonian Astrophysical Observatory and Harvard College ObservatoryCambridgeU.S.A.

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