Abstract/Details

ASTEROID TAXONOMY FROM CLUSTER ANALYSIS OF PHOTOMETRY


1984 1984

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Abstract (summary)

In the last few years, two major contributions to the asteroid database have been the eight-color and thermal radiometric surveys. The former consists of broad-band photometric measurements through eight filters spanning the 0.3 to 1.1 (mu)m wavelength range. The latter consists of thermal flux measurements at 10 and/or 20 (mu)m, and when combined with measures of the reflected light, can yield reliable estimates of their geometric albedos.

Visual display of the eight-color survey data can be simplified by reducing the dimensionality of the problem. A principal components analysis was performed to accomplish this task. The analysis shows that 95 percent of the information contained in the seven independent color indices is contained in two principal components. This result is due to the fact that most asteroid spectra can be explained in terms of two absorption features, one at ultraviolet and the other at near-infrared wavelengths.

The photometric and radiometric data sets were also used, along with cluster analysis techniques, to produce an improved asteroid taxonomic system. Seven major classes are now recognized and are designated A, C, D, E, M, P, and S. Three interesting minor classes are also identified: B, F, and G. Marginal evidence for an eighth major class, here called T, exists in the data, but the reality of this class awaits confirmation by further observations of potential members. Three asteroids do not fall into any of the above classes and are assigned unique designations: R (349 Dembowska), Q (1862 Apollo), and V (4 Vesta).

Four E-class asteroids are now known to exist in the main belt, yet nearly twice this number exist in or near the Hungaria region. Twenty eight D-class asteroids have been identified in the outer belt, where they represent a significant fraction of the population. Five D asteroids exist in the main belt, which one lying near the inner edge of the belt, which is dominated by S-class asteroids. Two of the interesting minor classes are associated with particular dynamical families. The Nysa family, with the single exception of Nysa itself, consists entirely of class F asteroids, while the B asteroids are found almost exclusively in the Themis family. The earth-approaching population is represented by at least two objects similar to Vesta and Dembowska, which are as many as are in the entire main belt, while most of the earth-approachers are of class S.

Indexing (details)


Subject
Astronomy;
Astrophysics
Classification
0606: Astronomy
0606: Astrophysics
Identifier / keyword
Pure sciences
Title
ASTEROID TAXONOMY FROM CLUSTER ANALYSIS OF PHOTOMETRY
Author
THOLEN, DAVID JAMES
Number of pages
162
Publication year
1984
Degree date
1984
School code
0009
Source
DAI-B 45/07, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
University/institution
The University of Arizona
University location
United States -- Arizona
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
8421985
ProQuest document ID
303340866
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/303340866
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