Poster De Conférence Année : 2024

Modeling the possible magnetic properties of the MMx Phobos sample

Résumé

The JAXA Martian Moons eXplorer (MMx) mission plans to return for the first time a sample of the soil of Phobos, the main moon of Mars. The primary goal of this ambitious mission is to understand the formation of the moons of Mars. Two main models have been proposed: either Phobos and Deimos are asteroids formed far from Mars and subsequently captured by it, or they are products of a giant collision that occurred early in Mars’ history. As part of the laboratory analyses of the returned samples, we propose measuring their magnetic properties to test the giant impact scenario. In this, the material blasted into orbit by the collision cools down in space and, depending on the timing of the collision, may record the magnetic field generated by Mars at that time. Measuring the properties of the sample resulting from thermoremanent magnetization (TRM) should allow us to constrain the processes that occurred during its formation by a giant collision. We present here a physical model of TRM of fully molten rocky material cooling down while orbiting Mars. We first describe the cooling process, then compute the magnetic field strength experienced by the magnetic minerals as a function of the distance to Mars, when the temperature crosses the Curie temperature of the material. The remanent magnetization is determined for different compositions and magnetic properties of the material. In these calculations, we pay particular attention to the spatial coherence of magnetization, which can be expected for material condensed in space and then accreted whilst in orbit around Mars. Measuring the magnetization coherency scale can thus give insights into the accretion processes occurring in the circum-Martian disk of debris during the cooling and crystallization of the material. Finally, we discuss the protocol that should be implemented to enable laboratory measurements of the magnetic properties of the samples from Phobos.

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Dates et versions

hal-04628222 , version 1 (28-06-2024)

Identifiants

  • HAL Id : hal-04628222 , version 1

Citer

Pascal Rosenblatt, Clara Maurel, Jérôme Gattacceca, Jean Duprat, Mariko Dunseath-Terao, et al.. Modeling the possible magnetic properties of the MMx Phobos sample. 45th COSPAR Scientific Assembly - COSPAR 2024, Jul 2024, Busan, South Korea. , Scientific Commission/Panel B, B1.1-0032-24. ⟨hal-04628222⟩
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