Iron Rain: measuring the occurrence rate and origin of small iron meteoroids at Earth
| Autor: | Althea V. Moorhead, Peter Brown, Peter S. Gural, Tristan Mills, D. Vida, Michael J. Mazur |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Earth and Planetary Astrophysics (astro-ph.EP)
Meteor (satellite) Physics education.field_of_study Brightness 010504 meteorology & atmospheric sciences Meteoroid Population FOS: Physical sciences Chondrule Astronomy and Astrophysics Astrophysics Light curve 01 natural sciences Meteorite 13. Climate action Space and Planetary Science Chondrite 0103 physical sciences education 010303 astronomy & astrophysics 0105 earth and related environmental sciences Astrophysics - Earth and Planetary Astrophysics |
| Popis: | We report results of a four-year survey using Electron Multiplied Charged Coupled Device (EMCCD) cameras recording 34761 two-station video meteor events complete to a limiting magnitude of +6. The survey goal was to characterize probable iron meteoroids. Using only physical properties of the meteor trajectories including early peaking light curves, short luminous trajectories, and high energies accumulated per area at beginning, we identified 1068 iron meteors. Our iron candidates are most abundant at slow speeds < 15 km/s, where they make up approximately 20% of the mm-sized meteoroid population. They are overwhelmingly on asteroidal orbits, and have particularly low orbital eccentricities and smaller semi-major axes when compared to non-irons between 10-20 km/s. Our iron population appears to be more numerous at fainter magnitudes, comprising 15% of slow (10-15 km/s) meteors with peak brightness of +3 with the fraction rising to 25% at +6 to +7, our survey limit. The iron orbits are most consistent with an asteroidal source and are in highly evolved orbits, suggesting long collisional lifetimes (107 years). Metal-rich chondrules (nodules) found in abundance in EL Chondrites are one possible source for this population. We also propose a possible technique using R-band colours to more robustly identify fainter iron meteors with very high confidence. Accepted for publication in MNRAS on September 21st, 2021. 13 pages, 21 figures |
| Databáze: | OpenAIRE |
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