Mutual event observations of solar system objects by SRC on Mars Express

Abstract

Context. Both Martian moons, Phobos and Deimos, have been observed during several imaging campaigns by the Super Resolution Channel (SRC) on the Mars Express probe. Several tens of images are obtained during mutual event observations – when the Martian moons are both observed or together with another solar system body. These observations provide new opportunities to determine the bodies’ positions in their orbits. Aims. A method was sought to automate the observation of the positions of the imaged bodies. Within one image sequence a similarly accurate localization of the objects in all images should be possible. Methods. Shape models of Phobos and Deimos are applied to simulate the appearance of the bodies in the images. Matching the illuminated simulation against the observation provides a reliable determination of the bodies’ location within the image. To enhance the matching confidence several corrections need to be applied to the simulation to closely reconstruct the observation. Results. A list of 884 relative positions between the different objects is provided through the Centre de Données astronomiques de Strasbourg (CDS).