AAS 207th Meeting, 8-12 January 2006
Session 154 Planetesimals, Protostellar Disks and Cosmic Rays
Oral, Wednesday, 10:00-11:30am, January 11, 2006, Balcony C/D

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[154.02] Minor Planets as a Probe of the Gravitational Field in the Outer Solar System

G. L. Page, J. F. Wallin (George Mason University), D. S. Dixon (Jornada Observatory)

After passing beyond 20 AU, and out to a distance beyond 75 AU, both Pioneer 10 and 11 showed systematic errors in their trajectories that could be explained by a constant acceleration towards the sun. This anomalous acceleration has come to be called the Pioneer Effect, and although spacecraft systematics are its most likely explanation, there have been no convincing arguments that that is indeed the case. The possibility that the Pioneer Effect represents a real phenomenon is attractive for many reasons; however, what is lacking is a means of measuring it. We show that comets and asteroids can be used to assess the gravitational field in the outer solar system and thereby investigate the Pioneer Effect. This is possible because minor planets have a large enough mass to avoid most nongravitational perturbations and are sufficiently large and bright that they can be observed for useful intervals. We discuss the utility of a long-term observation program to monitor such bodies and assess the reality of the Pioneer Effect. More broadly, since there are few intermediate range tests of gravity at the multiple AU distance scale, we discuss use of these bodies to assess the gravitational field in the outer solar system. Thus, such an observation program could have profound effects on our understanding of the mass distribution in the outer solar system, and could assist in discriminating between alternative gravitational theories such as MOND and classical gravity, as well as more exotic gravitational theories.

The author(s) of this abstract have provided an email address for comments about the abstract: gpage@gmu.edu

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