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Communication Dans Un Congrès Année : 2009

Phobos grooves formation from Stickney impact ejecta: a simulation

Michel Hamelin
  • Fonction : Auteur

Résumé

Although grooves are common on asteroids, on Phobos the grooves have been the subject of many various formation hypotheses for two reasons: the fact that Phobos is orbiting around Mars close to the Roche limit that implies an unusual gravity environment, and also the fact that the huge crater impact, Stickney, seems to be related at least to a family of grooves radial to this crater. However, some authors claim that these grooves could have been formed not from the Stickney impact, but from martian crater ejecta hitting Phobos. The present study explores the first idea by computing the trajectory of a test mass gliding on the surface of Phobos for any initial position and velocity. An ellipsoidal model of Phobos is used for both the gravity and surface geometry. Depending on these initial conditions a gliding mass stay gliding or can take off after some distance. Generally the trajectories are not ‘down hill’ as the motion is strongly dependent on the velocity. Then the main objections to the hypothesis that gliding or rolling blocks could have dug these grooves fail. As the Stickney impact occurred at larger distances from Mars, the study is extended to the ancient Phobos in its drift towards Mars and then the various hypotheses for the grooves formation are discussed.
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Dates et versions

hal-04113567 , version 1 (01-06-2023)

Identifiants

Citer

Michel Hamelin. Phobos grooves formation from Stickney impact ejecta: a simulation. European Planetary Science Congress 2009, Sep 2009, Potsdam (Germany), Germany. pp.EPSC2009-138. ⟨hal-04113567⟩
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