Lost City meteorite-Its recovery and a comparison with other fireballs

McCrosky, R. E.; Posen, A.; Schwartz, G.; Shao, C. Y.

doi:10.1029/jb076i017p04090

Cited by 146 publications

(75 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Details on all previous work are summarized in Ceplecha (1988 Bodies larger than 0.1 kg can be better classified according to their ability to penetrate the atmosphere. These bodies produce fireballs and our knowledge of them comes from photographic observations of fireball networks (EN, PN, MORP;Ceplecha, 1988;Ceplecha and McCrosky, 1969;McCrosky et al, 1971;Halliday et ο/., 1984Halliday et ο/., , 1989. Except for very early portions, the ablation part of their trajectories is practically identical with their luminous trajectories.…”

Section: Classification From Preheating and Ablationmentioning

confidence: 99%

Meteoroid Properties from Photographic Records of Meteors and Fireballs

Ceplecha

1994

Symp. - Int. Astron. Union

View full text Add to dashboard Cite

Abstract. Statistical criteria based on the single-body theory enabled the distinction of different composition groups of meteoroids in the past. The new single-body model proposed by Ceplecha (1983, 1984) is capable of determining the individual values of ablation coefficients, which has proved to be a better tool for separating meteoroids of different ablation properties. However, a significant fraction of fireballs exhibit a time-dependence of residuals, when the single-body model is applied to their photographic observations. This was recently explained by assuming sudden fragmentation at a point (gross-fragmentation). The proposed gross-fragmentation model was checked in exceptional cases, when splitting of a fireball was directly visible on the photographs. The new fragmentation model was then applied to the best photographic records of Prairie Network fireballs (PN). Least-squares fit of computed to observed distances along a meteoroid trajectory determines uniquely the ablation coefficient, the shape-density coefficient, the position of the gross-fragmentation point and the amount of fragmented material relative to the main body mass. This enabled not only a better classification according to ablation coefficient (composition groups), but also a recognition of different strength categories according to dynamic pressure at the fragmentation point. Except for composition groups (types) I, II, III A, HIB, each meteoroid with precise photographic data on its fireball can be classified as NF (no-fragmenting), IF (with one point of fragmentation) and MF (with many points of fragmentation). The fragmenting meteoroids (IF and MF) can moreover be sorted into several categories (a, 6, c, if, e) according to dynamic pressure at the fragmentation point. Thus the classification became two dimensional, separating meteoroid composition from structure. Values of ablation coefficients and bulk-densities were revised using this model. The amount of fragmented mass relatively to the main body was also determined. Typical sudden fragmentation for almost half of all fragmenting meteoroids is equivalent to stripping away slightly more than half of the mass. Classification from preheating and ablation.When a meteoroid collides with the Earth's atmosphere, most of the mutual kinetic energy is freed in interaction processes. The meteor phenomenon is thus very much dependent on the composition and structure of the meteoroid. Even the preheating is a sensitive indicator of the physical properties of the material from which the meteor body is composed.The beginning heights of the luminous trajectories can thus be used for classification of meteoroids (Ceplecha 1967(Ceplecha , 1968. This was done in the past for bodies in the mass range from 2 χ 10~8 kg to 0.5 kg by recognizing different discrete levels of beginning heights. Four groups denoted A, B, C, and D can be specified. The A group meteors start their luminous trajectory much lower down than the D group meteors. The ratio of the air density at the beginning height between ...

show abstract

Section: Classification From Preheating and Ablationmentioning

confidence: 99%

Meteoroid Properties from Photographic Records of Meteors and Fireballs

Ceplecha

1994

Symp. - Int. Astron. Union

View full text Add to dashboard Cite

show abstract

“…Fred L. Whipple was again with it as the director of the Smithsonian Astrophysical Observatory, when the effort of R. E. McCrosky resulted in operating the Prairie Network for fireballs. (McCrosky and Posen 1968). A recent study of populations among fireballs were based on data of 232 events photographed by the Prairie Network during 7 years.…”

Section: Statistical Studies Of the Photographic Data On Atmospheric mentioning

confidence: 99%

5. Meteoroid Populations and Orbits

Ceplecha¹

1977

International Astronomical Union Colloquium

View full text Add to dashboard Cite

“…(1964 to 1975) and the All-Sky Network in Czechoslovakia (1958 to date) observed hundreds of bright meteors, but very ' few meteorites were recovered [McCrosky et al, 1971]. Apparently, most meteoroids are totally ablated in the atmosphere and, hence, large quantities ' of ablation material must reach the earth's surface in a finely divided state.…”

Section: Introductionmentioning

confidence: 99%

Analysis of ablation debris from natural and artificial iron meteorites

Blanchard¹,

Davis²

1978

J. Geophys. Res.

View full text Add to dashboard Cite

Artificial ablation studies have been performed on iron and nickel‐iron samples by using an arc‐heated plasma of ionized air. Experiment conditions simulated a meteoroid traveling about 12 km/s at an altitude of 70 km. The artificially produced fusion crusts and ablation debris show features very similar to natural fusion crusts of the iron meteorites Boguslavka, Norfork, and N'Kandhla and to magnetic spherules recovered from deep‐sea Mn nodules. X ray diffraction, electron microprobe, optical, and scanning electron microscope analyses revealed that important mineralogical, elemental, and textural changes occur during ablation. Some metal is melted and ablated. The outer margin of the melted rind is oxidized and recrystallizes as a discontinuous crust of magnetite and wüstite. Adjacent to the oxidized metallic ablation zone is an unoxidized metallic zone in which structures such as Widmannstatten bands are obliterated as the metal is transformed to unequilibrated α2 nickel‐iron. Volatile elements such as S and P are vaporized in the ablation zone. Less volatile elements such as Si and Mn undergo fractionation and are concentrated in the oxide phases, while Ni is concentrated in the metal phases. Dissimilar phases form an intimate intergrowth that persists to a submicroscopic level. Identification of meteor ablation debris in particle collections cannot be based on a single parameter; elemental and mineralogical composition as well as morphological and textural features must be considered.

show abstract

Lost City meteorite-Its recovery and a comparison with other fireballs

Cited by 146 publications

References 8 publications

Meteoroid Properties from Photographic Records of Meteors and Fireballs

Meteoroid Properties from Photographic Records of Meteors and Fireballs

5. Meteoroid Populations and Orbits

Analysis of ablation debris from natural and artificial iron meteorites

Contact Info

Product

Resources

About