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Discovery of Asteroid 1976 AA

Helin, Eleanor F. and Shoemaker, Eugene M. (1977) Discovery of Asteroid 1976 AA. Icarus, 31 (4). pp. 415-419. ISSN 0019-1035. doi:10.1016/0019-1035(77)90142-7.

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Asteroid 1976 AA was discovered as a result of a continuing systematic search for planet-crossing asteroids. It is the first asteroid to be thoroughly investigated by means of photometry and radiometry on its discovery apparition. It is also the first asteroid found with a semimajor axis and period less than that of the Earth and the first Earth-crossing asteroid which does not cross the orbit of either Mars or Venus. We estimate that there might be several tens of objects to absolute magnitude 18, which are exclusively Earth crossing. Some of these objects might be exceptionally easy to reach by spacecraft.

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Additional Information:Copyright © 1977 Published by Elsevier Inc. Received October 1, 1976; revised January 20, 1977. We wish to thank Hale Observatories for extensive observing time on the 18-in. Schmidt camera, which has made our systematic search possible. We also wish to acknowledge the many observers around the world who provided follow-up observations of newly discovered objects, especially of 1976 AA. J. G. Williams, B. G. Marsden, and D. L. Matson have been of great help to us throughout the program. The research has been supported by the Planetology Programs Office of the National Aeronautics and Space Administration under Grant NGR-05-002-303.
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Caltech Division of Geological and Planetary Sciences2813
Issue or Number:4
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Official Citation:Eleanor F. Helin, Eugene M. Shoemaker, Discovery of asteroid 1976 AA, Icarus, Volume 31, Issue 4, August 1977, Pages 415-419, ISSN 0019-1035, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48332
Deposited By: George Porter
Deposited On:12 Aug 2014 14:33
Last Modified:10 Nov 2021 18:31

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