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| Formato: | Preprint |
| Publicado: |
2025
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| Acceso en línea: | https://arxiv.org/abs/2501.03308 |
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| _version_ | 1866916553162752000 |
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| author | Chow, Ian Brown, Peter G. |
| author_facet | Chow, Ian Brown, Peter G. |
| contents | Numerous decameter-sized asteroids have been observed impacting Earth as fireballs. These objects can have impact energies equivalent to hundreds of kilotons of TNT, posing a hazard if they impact populated areas. Previous estimates of meteoroid flux using fireball observations have shown an Earth impact rate for decameter-size objects of about once every $2$-$3$ years. In contrast, telescopic estimates of the near-Earth asteroid population predict the impact rate of such objects to be of order $20$-$40$ years, an order-of-magnitude difference. While the cause of this discrepancy remains unclear, tidal disruption of a larger near-Earth body has been proposed as an explanation for these excess decameter-sized impactors. The release in 2022 of previously classified United States Government (USG) satellite sensor data for fireball events has provided a wealth of new information on many of these impacts. Using this newly available USG sensor data, we present the first population-level study characterizing the orbital and dynamical properties of 14 decameter-sized Earth impactors detected by USG sensors since 1994, with a particular focus on searching for evidence of tidal disruption as the cause of the impact rate discrepancy. We find there is no evidence for recent ($\lesssim 10^4$ years) tidal disruption and weak evidence for longer-term tidal disruption in the decameter impactor population, but that the latter conclusion is limited by small number statistics. We also investigate the origins of both the impactor and near-Earth asteroid populations of decameter-sized objects from the main asteroid belt. We find that both populations generally originate from the same source regions: primarily from the $ν_6$ secular resonance ($\sim70$%) with small contributions from the Hungaria group ($\sim20$%) and the 3:1 Jupiter mean-motion resonance ($\sim10$%). |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_03308 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Decameter-sized Earth impactors -- I: Orbital properties Chow, Ian Brown, Peter G. Earth and Planetary Astrophysics Numerous decameter-sized asteroids have been observed impacting Earth as fireballs. These objects can have impact energies equivalent to hundreds of kilotons of TNT, posing a hazard if they impact populated areas. Previous estimates of meteoroid flux using fireball observations have shown an Earth impact rate for decameter-size objects of about once every $2$-$3$ years. In contrast, telescopic estimates of the near-Earth asteroid population predict the impact rate of such objects to be of order $20$-$40$ years, an order-of-magnitude difference. While the cause of this discrepancy remains unclear, tidal disruption of a larger near-Earth body has been proposed as an explanation for these excess decameter-sized impactors. The release in 2022 of previously classified United States Government (USG) satellite sensor data for fireball events has provided a wealth of new information on many of these impacts. Using this newly available USG sensor data, we present the first population-level study characterizing the orbital and dynamical properties of 14 decameter-sized Earth impactors detected by USG sensors since 1994, with a particular focus on searching for evidence of tidal disruption as the cause of the impact rate discrepancy. We find there is no evidence for recent ($\lesssim 10^4$ years) tidal disruption and weak evidence for longer-term tidal disruption in the decameter impactor population, but that the latter conclusion is limited by small number statistics. We also investigate the origins of both the impactor and near-Earth asteroid populations of decameter-sized objects from the main asteroid belt. We find that both populations generally originate from the same source regions: primarily from the $ν_6$ secular resonance ($\sim70$%) with small contributions from the Hungaria group ($\sim20$%) and the 3:1 Jupiter mean-motion resonance ($\sim10$%). |
| title | Decameter-sized Earth impactors -- I: Orbital properties |
| topic | Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2501.03308 |