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Ceplecha, Z.; Borovička, J.; Elford, W. G.; Revelle, D. O.; Hawkes, R. L.; Porubčan, V.; Šimek, M.

doi:10.1023/a:1005069928850

Cited by 753 publications

(496 citation statements)

References 192 publications

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“…Because of the large diversity between the meteorite and meteoroid physical properties, we consider two grossly different cases (e.g., Ceplecha et al 1998): (i) ordinary chondrite-like (OC for short) material analogous to the group I meteoroids; and (ii) primitive carbonaceous chondrite-like (CC for short) material analogous to the group III meteoroids. Some physical parameters of OC and CC materials have been determined from direct laboratory measurements of the corresponding meteorite samples (e.g., Yomogida & Matsui 1983;Medvedev et al 1985;Britt & Consolmagno 2003).…”

Section: Materials Parametersmentioning

confidence: 99%

“…In this situation, we basically adopted the same parametric relationships as given above for the OC class with the following modifications: (i) the nominal tensile strength σ t0 in Eq. (29) was given a value of −2 MPa to express the weaker nature of CCs compared with OCs (the assumed order of magnitude difference between the σ t0 values roughly corresponds to the difference between the observationally-determined dynamic pressures of the group I and III meteoroids; e.g., Ceplecha et al 1998;Borovička 2007); (ii) the thermal conductivity et al 2010) was considered in Eq. (28); and (iii) the albedo value A = 0 and thermal emissivity = 1 was considered in this case to be consistent with the overall darker character of the CC material.…”

Section: Carbonaceous Chondrite (Group Iii) Materialsmentioning

confidence: 99%

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Thermal stresses in small meteoroids

Čapek

Vokrouhlický

2010

A&A

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Aims. We evaluate thermal stresses in small, spherical, and homogeneous meteoroids with elastic rheology and regular rotation. The temperature variations are caused by the absorbed sunlight energy being conducted into the interior layers of the body. Our model assumes arbitrary thermal conductivity value, but restricts itself to a linearized treatment of the boundary conditions of the heat diffusion problem. We consider the diurnal insolation cycle only as if the body were in a fixed position along its heliocentric orbit. This constrains the upper limit to the object size to which our modeling is applicable. Methods. We derive analytical expressions for the components of the thermal stress tensor throughout the body. Using two sets of material properties (ordinary and carbonaceous chondrites), we study the conditions required for material failure caused by thermal stress leading to fission. Results. Our results indicate that the onset of thermal failure in the meteoroid depends on a number of parameters including the heliocentric distance, the size, the rotation frequency, and the orientation of the spin axis with respect to the solar direction. In our case, we find large, centimeter-to meter-size, slowly rotating meteoroids or those with a spin axis pointing towards the Sun or both, are the most susceptible to the thermal bursting. This may have implications for the (i) size distribution of meteoroids in various streams depending on their heliocentric orbit and the physical characteristics of their parent bodies; (ii) orbital distribution of sporadic complexes of meteoroids in the planet-crossing zone; and/or (iii) fate of fragments released during comet disintegration events, especially those with low perihelia (e.g., Kreutz class).

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Section: Materials Parametersmentioning

confidence: 99%

Section: Carbonaceous Chondrite (Group Iii) Materialsmentioning

confidence: 99%

Thermal stresses in small meteoroids

Čapek

Vokrouhlický

2010

A&A

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“…From the 1950s onward, transmission gratings largely replaced prisms in meteor spectrographs. Extensive spectroscopic programs were carried out in the USA, Canada, the former USSR, and former Czechoslovakia (Ceplecha et al 1998). Hemenway et al (1971) used a sensitive video technique to observe meteor spectra for the first time.…”

Section: Introductionmentioning

confidence: 99%

Catalogue of representative meteor spectra

Vojáček

Borovička

Koten

et al. 2015

A&A

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Aims. We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to −3, corresponding to meteoroid sizes from 1 mm to 10 mm. Methods. Parallel double-station video observations allowed us to compute heliocentric orbits for all meteors. Most observations were performed during the periods of activity of major meteor showers in the years between 2006 and 2012. Spectra are classified according to relative intensities of the low-temperature emission lines of Mg, Na, and Fe. Results. Shower meteors were found to be of normal composition, except for Southern δ Aquariids and some members of the Geminid shower, neither of which have Na in the meteor spectra. Variations in Na content are typical for the Geminid shower. Three populations of Na-free mereoroids were identified. The first population are iron meteorites, which have an asteroidal-chondritic origin, but one meteoroid with low perihelion (0.11 AU) was found among the iron meteorites. The second population were Sun-approaching meteoroids in which sodium is depleted by thermal desorption. The third population were Na-free meteoroids of cometary origin. Long exposure to cosmic rays on the surface of comets in the Oort cloud and disintegration of this crust might be the origin of this population of meteoroids.

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“…Each meteoroid will have different ablation behaviour due to its composition, structure, bulk density and size. For example, the beginning heights and lightcurve shapes of faint meteors show significant variation, while larger meteors vary in end height (Ceplecha et al 1998). Koten et al (2004) showed that the differences in lightcurves and beginning heights among major video meteor showers can be explained by differences in the chemical composition and physical structure of their parent bodies.…”

Section: Introductionmentioning

confidence: 99%

Bulk density of small meteoroids

Kikwaya

Campbell-Brown

Brown

2011

A&A

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Aims. Here we report on precise metric and photometric observations of 107 optical meteors, which were simultaneously recorded at multiple stations using three different intensified video camera systems. The purpose is to estimate bulk meteoroid density, link small meteoroids to their parent bodies based on dynamical and physical density values expected for different small body populations, to better understand and explain the dynamical evolution of meteoroids after release from their parent bodies. Methods. The video systems used had image sizes ranging from 640 × 480 to 1360 × 1036 pixels, with pixel scales from 0.01 • per pixel to 0.05 • per pixel, and limiting meteor magnitudes ranging from M v = +2.5 to +6.0. We find that 78% of our sample show noticeable deceleration, allowing more robust constraints to be placed on density estimates. The density of each meteoroid is estimated by simultaneously fitting the observed deceleration and lightcurve using a model based on thermal fragmentation, conservation of energy and momentum. The entire phase space of the model free parameters is explored for each event to find ranges of parameters which fit the observations within the measurement uncertainty. Results. (a) We have analysed our data by first associating each of our events with one of the five meteoroid classes. The average density of meteoroids whose orbits are asteroidal and chondritic (AC) is 4200 kg m −3 suggesting an asteroidal parentage, possibly related to the high-iron content population. Meteoroids with orbits belonging to Jupiter family comets (JFCs) have an average density of 3100 ± 300 kg m −3 . This high density is found for all meteoroids with JFC-like orbits and supports the notion that the refractory material reported from the Stardust measurements of 81P/Wild 2 dust is common among the broader JFC population. This high density is also the average bulk density for the 4 meteoroids with orbits belonging to the Ecliptic shower-type class (ES) also related to JFCs. Both categories we suggest are chondritic based on their high bulk density. Meteoroids of HT (Halley type) orbits have a minimum bulk density value of 360 +400 −100 kg m −3 and a maximum value of 1510 +400 −900 kg m −3 . This is consistent with many previous works which suggest bulk cometary meteoroid density is low. SA (Sun-approaching)-type meteoroids show a density spread from 1000 kg m −3 to 4000 kg m −3 , reflecting multiple origins. (b) We found two different meteor showers in our sample: Perseids (10 meteoroids, ∼11% of our sample) with an average bulk density of 620 kg m −3 and Northern Iota Aquariids (4 meteoroids) with an average bulk density of 3200 kg m −3 , consistent with the notion that the NIA derive from 2P/Encke.

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Cited by 753 publications

References 192 publications

Thermal stresses in small meteoroids

Thermal stresses in small meteoroids

Catalogue of representative meteor spectra

Bulk density of small meteoroids

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