NOAO > Library > NOAO Preprint Series > Preprint 897
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NOAO > Library > NOAO Preprint Series > Preprint 897 |
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Author(s): Mueller, B.E.A., Samarasinha, N.H., and Belton, M.J.S.
Title: The Diagnosis of Complex Rotation in
the
Lightcurve of 4179 Toutatis and
Potential Applications to Other
Asteroids and Bare Comary Nuclei
Abstract:
The analysis of radar observations of the asteroid 4179 Toutatis by Hudson and
Ostro (1995) yielded a complex spin state. We revisit the visible lightcurve
data on Toutatis (Spencer et al. 1995) to explore the feasibility of using a
rotational lightcurve to recover the signature of an excited spin state. For
this, we apply Fourier transform and CLEAN algorithms (WindowCLEAN).
WindowCLEAN
yields clear and precise frequency signatures associated with the precession
of
the long axis about the total angular momentum vector and a combination of
this
precession and rotation about the long axis. For a long axis mode (LAM) state,
our periodicities for Toutatis yield a mean long axis precession period,
P_\phi,
of 7.38 dy and a rotation period around the long axis, P_\psi, of 5.38dy which
compare well with the respective periods of 7.42 dy and 5.37dy derived by
Ostro
et al. (1999) and represent an independent confirmation of these values. We
explain why the dramatic change in the Earth-
Toutatis-sun geometry during the time that the lightcurve was obtained, has
little effect on the final results obtained. Using the Toutatis example as a
guide, we discuss the capabilities as well as the limitations on deriving
information about complex spin states from asteroidal lightcurves.
Date Received:
May 03, 2002
Publication Info:
Icarus 158:305-311
Downloadable version (3542 Kb PDF)
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NOAO > Library > NOAO Preprint Series > Preprint 897 |
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