Hostname: page-component-848d4c4894-x5gtn Total loading time: 0 Render date: 2024-06-01T21:11:46.088Z Has data issue: false hasContentIssue false
  • English
  • Français

2. Asteroid Compositional Types and their Distributions

Published online by Cambridge University Press:  12 April 2016

B. Zellner  and
E. Bowell

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

A sample of 359 minor planets with available colorimetric, spectropnotometric, thermal-radiometric, and/or polarimetrie data are classified into broadly defined compositional types C (carbonaceous), S (silicaceous), M (metal-rich), E (metal-free; enstatite?), O (ordinary-chondritic?), T (Trojan; unidentified composition), and U (unclassifiable; none of the above).

The small asteroids in Mars- or earth-crossing orbits are almost invariably of type S or O. For the main belt between 2.2 and 3.5 AU., distributions of the various types over diameter and orbital parameters are derived with corrections for observational selection bias. For 560 main-belt asteroids with diameters >50 km, 76% are of type C, 16% of type S, 5% M, and 3% of other types. The S objects become progressively less common with distance. The shapes of the diammeter-frequency relations for primitive (C) and evolved (S + M) types are statistically indistinguishable, both showing a change of slope at 160-km diameter.

While large asteroids avoid the Kirkwood gaps more strongly than small ones, we find no significant gap-related anomalies in the relative frequencies of compositional types. Thus most of the observational basis for models in which primitive and evolved asteroids respond differently to collisional evolution has been removed.

Type
Part IV. Physical Nature of Asteroids
Information
International Astronomical Union Colloquium , Volume 39: Comets, Asteroids, Meteorites: Interrelations, Evolution and Origins , December 1977 , pp. 185 - 197
Copyright
Copyright © A.H. Delsemme 1977

References

Bowell, E. 1977, Icarus, in preparation.Google Scholar
Bowell, E., Chapman, C. R., Gradie, J. C., Morrison, D., and Zellner, B. 1977, Icarus, in preparation.Google Scholar
Chapman, C. R. 1974, Geophys. Res. Lett., 1, 341.Google Scholar
Chapman, C. R. 1976, Geochim. Cosmochim. Acta, 40, 701.Google Scholar
Chapman, C. R., and Davis, D. R. 1975, Science, 190, 553.Google Scholar
Chapman, C. R., Morrison, D., and Zellner, B. 1975, Icarus, 25, 104.Google Scholar
Cruikshank, D. P. 1976, Bull. Amer. Astron. Soc., in press; Icarus, in press.Google Scholar
Dollfus, A. this volume.Google Scholar
Gaffey, M. J. 1974, Ph.D. Thesis, Massachusetts Institute of Technology.Google Scholar
Gehrels, T., and Gehrels, N. 1977, Astron. J., in preparation.Google Scholar
Hansen, O. 1976, Astron. J., 81, 74.Google Scholar
Hansen, O. this volume.Google Scholar
Houten, C. J. van. 1971, in Physical Studies of Minor Planets, ed. Gehrels, T. (Washington: NASA SP-267), p. 294.Google Scholar
Johnson, T. V., and Fanale, F. P. 1973, J. Geophys. Res., 78, 8507.Google Scholar
Larson, H. P., and Fink, U. 1975, Icarus, 26, 420.Google Scholar
Lebofsky, L. A., Veeder, G. J., Zellner, B., and Lebofsky, M. J. 1977, in preparation.Google Scholar
Levin, B. J., Simonenko, A. N., and Anders, E. 1976, Icarus, 28, 307.Google Scholar
McCord, T. B., Adams, J. B., and Johnson, T. V. 1970, Science 168, 1445.Google Scholar
McCord, T. B., and Chapman, C. R. 1975a, Astrophys. J., 195, 553.Google Scholar
McCord, T. B., and Chapman, C. R. 1975b, Astrophys. J., 197, 781.Google Scholar
McCord, T. B., and Gaffey, M. J. 1974, Science, 186, 352.Google Scholar
McCord, T. B., and Gaffey, M. J. this volume.Google Scholar
Millis, R. L., Bowell, E., and Thompson, D. T. 1976, Icarus, 28, 53.Google Scholar
Morrison, D. this volume.Google Scholar
Morrison, D. 1977, Astrophys. J., in press.Google Scholar
Morrison, D., and Chapman, C. R. 1976, Astrophys. J., 204, 934.Google Scholar
Morrison, D., Zellner, B., and Leake, M. 1977, Icarus, in preparation.Google Scholar
Pieters, C., Gaffey, M. J., Chapman, C. R., and McCord, T. B. 1976, Icarus, 28, 105.Google Scholar
Zellner, B. 1975, Astrophys. J. Lett., 198, L45.Google Scholar
Zellner, B., Andersson, L., and Gradie, J. 1976, Icarus, in press.Google Scholar
Zellner, B., and Gradie, J. 1976a, Astron. J., 81, 262.Google Scholar
Zellner, B., and Gradie, J. 1976b, Icarus, 28, 117.Google Scholar
Zellner, B., Wisniewski, W. Z., Andersson, L., and Bowell, E. 1975, Astron. J., 80, 986.Google Scholar