Cartography for Martian Trojans

The last few months have seen the discovery of a second Martian Trojan (1998VF31), as well as two further possible candidates (1998 QH56 and 1998 SD4).Together with the previously discovered Martian satellite 5261 Eureka, theseare the only known possible solar system Trojan asteroids not associated withJupiter. Here, maps of the locations of the stable Trojan trajectories of Marsare presented. These are constructed by integrating an ensemble of in-plane andinclined orbits in the vicinity of the Martian Lagrange points for between 25million and 60 million years. The survivors occupy a band of inclinationsbetween 15 degrees and 40 degrees and longitudes between 240 degrees and 330degrees at the L5 Lagrange point. Around the L4 point, stable Trojans inhabittwo bands of inclinations (15 degrees < i < 30 degrees and 32 degrees < i < 40degrees) with longitudes restricted between 25 degrees and 120 degrees. Both5261 Eureka and 1998 VF31 lie deep within one of the stable zones, whichsuggests they may be of primordial origin. Around Mars, the number of suchundiscovered primordial objects with sizes greater than 1 km may be as high as50. The two candidates 1998 QH56 and 1998 SD4 are not presently on Trojanorbits and will enter the sphere of influence of Mars within half a millionyears.Comment: 14 pages, 3 figures, in press at the Astrophysical Journal (Letters