Rotation of cometary meteoroids

Čapek, D.

doi:10.1051/0004-6361/201423857

Cited by 5 publications

(6 citation statements)

References 41 publications

(62 reference statements)

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“…Thus, the range to the target can be used as an initial NEO and mini-moon identification. If the orbit of the object can be determined, this would be a very reliable method of identification as NEOs and mini-moons generally have vastly different orbits compared to space debris (Fedorets et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…The Jet Propulsion Laboratory (JPL) CNEOS maintains a database of NEO close approaches. This database contains objects that have close encounters with the Earth and provides information, such as the date and distance for the closest approaches (Chesley and Chodas, 2002). As the database D. Kastinen et al: Radar observability of near-Earth objects with EISCAT 3D consists of known objects, not modelled populations, there are significantly more past encounters than projected future encounters.…”

Section: Known Neos With Close Approaches To the Earthmentioning

confidence: 99%

“…The theoretical models are based on a numerical analysis of the NEO capture probability, estimation of the average capture duration, and the estimated flux of NEOs into the capturable volume of phase space. Whereas Granvik et al (2012) focused on mini-moons only and estimated the flux based on the debiased NEO model by Bottke et al (2002), Fedorets et al (2017) extended the model to encompass both orbiters and fly-bys and tied the model to the updated NEO model by Granvik et al (2016).…”

Section: Mini-moon Modelmentioning

confidence: 99%

“…Here we use the newer mini-moon model by Fedorets et al (2017). The average mini-moon makes 3-4 revolutions around the Earth during a capture which lasts about 9 months.…”

Section: Mini-moon Modelmentioning

confidence: 99%

“…Most of the time, objects will make one single pass and then leave this region again. In some rare cases, the objects are temporarily captured by the Earth-Moon system (Granvik et al, 2012;Fedorets et al, 2017). These events are called temporarily captured fly-bys, if the object makes less than one revolution around the Earth, and temporarily captured orbiters, or minimoons, if the object makes one or more revolutions around the Earth.…”

Section: Introductionmentioning

confidence: 99%

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Radar observability of near-Earth objects using EISCAT 3D

et al. 2020

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Abstract. Radar observations can be used to obtain accurate orbital elements for near-Earth objects (NEOs) as a result of the very accurate range and range rate measureables. These observations allow the prediction of NEO orbits further into the future and also provide more information about the properties of the NEO population. This study evaluates the observability of NEOs with the EISCAT 3D 233 MHz 5 MW high-power, large-aperture radar, which is currently under construction. Three different populations are considered, namely NEOs passing by the Earth with a size distribution extrapolated from fireball statistics, catalogued NEOs detected with ground-based optical telescopes and temporarily captured NEOs, i.e. mini-moons. Two types of observation schemes are evaluated, namely the serendipitous discovery of unknown NEOs passing the radar beam and the post-discovery tracking of NEOs using a priori orbital elements. The results indicate that 60–1200 objects per year, with diameters D>0.01 m, can be discovered. Assuming the current NEO discovery rate, approximately 20 objects per year can be tracked post-discovery near the closest approach to Earth. Only a marginally smaller number of tracking opportunities are also possible for the existing EISCAT ultra-high frequency (UHF) system. The mini-moon study, which used a theoretical population model, orbital propagation, and a model for radar scanning, indicates that approximately seven objects per year can be discovered using 8 %–16 % of the total radar time. If all mini-moons had known orbits, approximately 80–160 objects per year could be tracked using a priori orbital elements. The results of this study indicate that it is feasible to perform routine NEO post-discovery tracking observations using both the existing EISCAT UHF radar and the upcoming EISCAT 3D radar. Most detectable objects are within 1 lunar distance (LD) of the radar. Such observations would complement the capabilities of the more powerful planetary radars that typically observe objects further away from Earth. It is also plausible that EISCAT 3D could be used as a novel type of an instrument for NEO discovery, assuming that a sufficiently large amount of radar time can be used. This could be achieved, for example by time-sharing with ionospheric and space-debris-observing modes.

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Section: Discussionmentioning

confidence: 99%

Section: Known Neos With Close Approaches To the Earthmentioning

confidence: 99%

Section: Mini-moon Modelmentioning

confidence: 99%

“…Here we use the newer mini-moon model by Fedorets et al (2017). The average mini-moon makes 3-4 revolutions around the Earth during a capture which lasts about 9 months.…”

Section: Mini-moon Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Radar observability of near-Earth objects using EISCAT 3D

et al. 2020

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September epsilon Perseid cluster as a result of orbital fragmentation

Koten

Čapek

Spurný

et al. 2017

A&A

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Context. A bright fireball was observed above the Czech Republic on September 9, 2016, at 23:06:59 UT. Moreover, the video cameras at two different stations recorded eight fainter meteors flying on parallel atmospheric trajectories within less than 2 s. All the meteors belong to the September epsilon Perseid meteor shower. The measured proximity of all meteors during a very low activity meteor shower suggests that a cluster of meteors was observed. Aims. The goal of the paper is first to determine whether this event was a random occurrence or a real meteor cluster and second, if it was a cluster, to determine the epoch and at what distance from the Earth the separation of the particles occurred. Methods. The atmospheric trajectories of the observed meteors, masses, and relative distances of individual particles were determined using a double-station observation. According to the distances and masses of the particles, the most probable distance and time of fragmentation is determined. Results. The observed group of meteors is interpreted as the result of the orbital fragmentation of a bigger meteoroid. The fragmentation happened no earlier than 2 or 3 days before the encounter with the Earth at a distance smaller than ∼0.08 AU from the Earth.

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Three dimensional atmospheric entry simulation of a high altitude cometary dustball meteoroid

Hulfeld¹,

Küchlin²,

Jenny³

2021

A&A

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Aims. The break-up of a dustball meteoroid is investigated numerically based on fluid dynamics simulations of the meteoroid’s atmospheric entry flow. Both thermal and mechanical break-up mechanisms are implemented, in order to investigate dustball meteoroid disintegration. Methods. A three dimensional model of a dustball meteoroid composed of thousands of small spherical grains was used in the atmospheric entry flow simulation, performed with the direct simulation Monte Carlo (DSMC) method. The dynamics of each meteoroid grain were calculated by means of the discrete element method (DEM), which models contact dynamics between grains. By coupling DEM with DSMC, the dynamics of a dustball meteoroid were calculated during atmospheric entry. In addition, thermal computations were also carried out taking into account the incoming atmospheric heat flux, thermal radiation, and grain ablation. Thus, this methodology is able to compute mechanical as well as thermal dustball meteoroid disintegration. Results. To test this novel multi-physics simulation framework, a prototypical dustball meteoroid, namely a Draconid meteoroid, was simulated. Using typical material properties from the literature, the Draconid meteoroid was compressed due to aerodynamic forces to roughly half its size immediately after the start of the simulation at 200 km altitude. Later, aerodynamic-induced meteoroid rotation occured until the meteoroid disintegrated mechanically at 120 km altitude. The fact that the meteoroid disintegrated mechanically is directly related to the combination of material properties used in the simulation.

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Rotation of cometary meteoroids

Cited by 5 publications

References 41 publications

Radar observability of near-Earth objects using EISCAT 3D

Radar observability of near-Earth objects using EISCAT 3D

September epsilon Perseid cluster as a result of orbital fragmentation

Three dimensional atmospheric entry simulation of a high altitude cometary dustball meteoroid

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