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R.A. Juarez (New Mexico Tech), C.T. Martinez (University of New Mexico), W.H. Ryan, E.V. Ryan (MRO/NMT)
Photometric lightcurves were obtained during the 2002, 2004, and 2005 apparitions of the Vesta family asteroid 2511 Patterson using the 1.8-meter Vatican Advanced Technology Telescope (VATT) and the CTIO 1.0-meter. Analysis of these data yields a rotational period of 4.141 ± 0.001 hours and the following color indices: B-V = 0.91 ± 0.01, V-R = 0.50±0.01, and V-I = 0.81 ± 0.01. In addition, from January-May 2004, photometric data were aquired over a range of solar phase angles where a linear trend of 0.028 ± 0.001 mag/deg was observed in the asteroid's mean R magnitude. At low phase angles during March 2004, Patterson's lightcurve displayed an amplitude of approximately 0.7 magnitudes. Assuming a triaxial (a>b>c) ellipsoid model for its shape, this implies a minmum a/b axial ratio of 1.9. After observations from the 2005 apparition are completed, these will be combined with the previous data to develop a more complete shape model. This study will help place constraints on models for formation mechanisms of 2511 Patterson and the other Vesta family asteroids.
This work is supported by the NASA Planetary Astronomy Program and the generous observing time made available by the Vatican Observatory Research Group and NOAO. We also wish to thank Lacey Stewart and Quentin Jamieson for their assistance during the December 2002 and April 2004 observing runs.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.