The representation of asteroid shapes: A test for the inversion of Gaia photometry
Carbognani, A. and Tanga, P. and Cellino, A. and Delbo, M. and Mottola, S. and Marchese, E. (2012) The representation of asteroid shapes: A test for the inversion of Gaia photometry. Planetary and Space Science, 73 (1), pp. 80-85. Elsevier. DOI: doi:10.1016/j.pss.2011.12.002. ISSN 00320633.
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Official URL: http://dx.doi.org/10.1016/j.pss.2011.12.002
It is common practice nowadays to derive spins and 3D shapes of asteroids from the inversion of photometric lightcurves. However, this method requires, in general, a good number of photometric points and dedicated observing sessions. On the other hand, the photometric observations carried out by the Gaia mission will be sparse and their number relatively small. For this reason, a multi-parametric shape described by a large number of elementary facets cannot probably be derived from Gaia data alone. Therefore, the Data Processing and Analysis Consortium (DPAC), implemented a simpler solution as an unattended data reduction pipeline, which relies on three axial ellipsoids for the shape representation. However, overall accuracy of such triaxial shape solutions has to be assessed. How adequate is an ellipsoidal approximation to represent the overall properties of anirregular body? Which error is made on the volume in comparison to a more accurate model with irregular shape? To answer these questions, we have implemented numerical procedures for comparing ellipsoids to more complex and irregular shapes, and we performed a full simulation of the photometric signal from these objects, using both shape representations. Implementing the same software algorithm that will be used for the analysis of Gaia asteroid photometry, rotation period, spin axis orientation and ellipsoidal shape were derived from simulated observations of selected Main Belt asteroids assuming a geometric scattering model (work is in progress for more complex scattering models). Finally, these simulated Gaia results were compared to check the relevance of the ellipsoidal solution in comparison to multi-parametric shapes. We found that the ellipsoids by photometry inversion are closely similar to the best-fitting ellipsoids of the simulated complex shapes and that the error on the asteroid volume(relative to a complex shape is generally low, usually around 10%.
|Title:||The representation of asteroid shapes: A test for the inversion of Gaia photometry|
|Journal or Publication Title:||Planetary and Space Science|
|In Open Access:||No|
|In ISI Web of Science:||Yes|
|Page Range:||pp. 80-85|
|Keywords:||Asteroids photometry, Asteroids volume, Gaia mission|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Raumfahrt|
|HGF - Program Themes:||R EW - Erforschung des Weltraums|
|DLR - Research area:||Raumfahrt|
|DLR - Program:||R EW - Erforschung des Weltraums|
|DLR - Research theme (Project):||R - Vorhaben Exploration des Sonnensystems|
|Institutes and Institutions:||Institute of Planetary Research > Asteroids and Comets|
|Deposited By:||Dr.phys. Stefano Mottola|
|Deposited On:||04 Dec 2012 11:52|
|Last Modified:||07 Feb 2013 20:40|
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