Impakty, které poslaly meteoroidy k Zemi
| Thesis title in Czech: | Impakty, které poslaly meteoroidy k Zemi |
|---|---|
| Thesis title in English: | The impacts that send meteoroids to Earth |
| Key words: | impakt|meteoroidy |
| English key words: | impact|meteoroids |
| Academic year of topic announcement: | 2023/2024 |
| Thesis type: | diploma thesis |
| Thesis language: | |
| Department: | Astronomical Institute of Charles University (32-AUUK) |
| Supervisor: | doc. Mgr. Miroslav Brož, Ph.D. |
| Author: |
| Guidelines |
| According to observations and radiometric signatures, around 470\, My ago,
our planet witnessed a massive infall of L-chondrite meteoriods. The only plausible source of these meteoroids is a collision that created the asteroid family related to (20) Massalia. Observations also show that 40\,My ago, Massalia suffered another collision and formed a second family. Material from the more recent event makes almost 40\% of meteorite falls today (Marsset et al. submit., Brož et al. submit.). Our goal is to create a model for the respective collisions, using the smooth particle hydrodynamics (SPH) method. The computation should include a number physical processes, in particular, the impact itself, compression, decompression, deformation, vaporisation, shock wave, rarefaction wave, expansion, ejection, self-gravity, reaccumulation, merging, binary formation. We plan to use a state-of-the-art code, Opensph (Ševeček et al. 2021). The model will be constrained by the observed size-frequency distribution (SFD), the size, shape, and the current rotation state of (20) Massalia. In the near future, also the rotational states of small family members will be available (Ďurech & Hanuš 2023). At the same time, it is necessary to account for the abundance of dust produced by the 2nd impact, which is observed as the 1.4-deg dust band by IRAS (Nesvorný et al. 2006). This requires an extrapolation of the SFD to 100-$\mu$ sizes. The results will be also discussed in context of adaptive-optics observations by the VLT/SPHERE instrument, planned for late 2024. |
| References |
| Brož, M. et al., Young asteroid families as the primary source of meteorites.
Nature submit., https://arxiv.org/pdf/2403.08552. Ďurech, J., Hanuš, J., Reconstruction of asteroid spin states from Gaia DR3 photometry. Astron. Astrophys. 657, A24, 2023. Nesvorný, D. et al., Physical properties of asteroid dust bands and their sources. Icarus 181, 107, 2006. Marsset, M. et al., The Massalia asteroid family as the origin of ordinary L chondrites. Nature, submit., https://arxiv.org/abs/2403.08548. Ševeček, P., Simulations of asteroid collisions using a hybrid SPH/N-body approach. PhD Thesis, Charles Univ., 2021. Ševeček, P. et al., Impacts into rotating targets: angular momentum draining and efficient formation of synthetic families. Astron. Astrophys. 629, A122, 2019. |