A method to search for large-scale concavities in asteroid shape models
Abstract
Photometric light-curve inversion of minor planets has proven to produce a unique model solution only under the hypothesis that the asteroid is convex. However, it was suggested that the resulting shape model, for the case of non-convex asteroids, is the convex-hull of the true asteroid non-convex shape. While a convex shape is already useful to provide the overall aspect of the target, much information about real shapes is missed, as we know that asteroids are very irregular. It is a commonly accepted evidence that large flat areas sometimes appearing on shapes derived from light curves correspond to concave areas, but this information has not been further explored and exploited so far. We present in this paper a method that allows to predict the presence of concavities from such flat regions. This method analyses the distribution of the local normals to the facets composing shape models to predict the presence of abnormally large flat surfaces. In order to test our approach, we consider here its application to a large family of synthetic asteroid shapes, and to real asteroids with large-scale concavities, whose detailed shape is known by other kinds of observations (radar and spacecraft encounters). The method that we propose has proven to be reliable and capable of providing a qualitative indication of the relevance of concavities on well-constrained asteroid shapes derived from purely photometric data sets.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- November 2015
- DOI:
- 10.1093/mnras/stv1740
- Bibcode:
- 2015MNRAS.453.2232D
- Keywords:
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- minor planets;
- asteroids: general