Non-destructive controlled single-particle light scattering measurement Maconi, G.; Penttilä, A.; Kassamakov, I. ...
Journal of Quantitative Spectroscopy & Radiative Transfer/Journal of quantitative spectroscopy & radiative transfer,
January 2018, 2018-01-00, Letnik:
204
Journal Article
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•Our new device measures multi-wavelength light scattering of levitating particles.•The non-destructive approach enables research on highly valuable materials.•The measurement is calibrated by ...comparing acquired data to simulations.•We demonstrate our capabilities by measuring a Chelyabinsk meteorite sample.
We present a set of light scattering data measured from a millimeter-sized extraterrestrial rock sample. The data were acquired by our novel scatterometer, which enables accurate multi-wavelength measurements of single-particle samples whose position and orientation are controlled by ultrasonic levitation. The measurements demonstrate a non-destructive approach to derive optical properties of small mineral samples. This enables research on valuable materials, such as those returned from space missions or rare meteorites.
A new model of the atmospheric entry of the Neuschwanstein fireball has been developed. The fireball was photographed in Germany on April 6, 2002, and three fragments of it were found during a ...subsequent search in the territory predicted according to observations. In this study, the form of the meteoric body is assumed to be a cube with rounded vertices and edges. The estimated mass of the meteoric body at its entry into the atmosphere is close to the literature data obtained using seismic, acoustic, and infrasonic analysis. It is noted that the analysis of this fireball was for the first time made without using the photometric approach.
In this paper we examine the possibility of using approximations of elementary functions for the analytical solution of meteor physics equations, used to describe the trajectory and to evaluate the ...defining parameters of meteoroids entering the Earth’s atmosphere. We show the possibility of replacing the analytical solution with the combination of two elementary functions along one parameter. We provide estimates for the error of the proposed replacement. We investigate the magnitude of error in the function which arises in the approximation of meteoric observational data.
The general equation describing the motion of a meteoroid in the Earth’s atmosphere is considered. It is shown that, in this case, the momentum variation of the system consisting of the meteoroid and ...its separating mass is due to the velocity variation of the meteoroid. The projection of Newton’s equation onto the tangent to the meteoroid trajectory is analyzed. It is also shown that, because of large geocentric velocities (between 11 and 72 km/s), the dominant force is the drag force proportional to the square of the incident air flow velocity. Some numerical results obtained for the Bene>sov bolide registered by the European Fireball Network (May 7, 1991) are given as an illustrative example.
An approach to the estimation of the initial shape of a meteoroid based on the statistical distributions of masses of its recovered fragments is presented. The fragment distribution function is used ...to determine the corresponding scaling index of the power law with exponential cutoff. The scaling index is related empirically to the shape parameter of a fragmenting body by a quadratic equation, and the shape parameter is expressed through the proportions of the initial object. This technique is used to study a representative set of fragments of the Bassikounou meteorite and compare the obtained data with the results of statistical analysis of other meteorites.
The consequences of the impacts of cosmic bodies on the Earth’s surface are analyzed. The conditions of large craters formation on the solid surface of the planet are calculated using the recently ...introduced technique. The α-β parametric plane is used to determine the bounds for the areas in which craters with radii greater than 100 m, 1 km, and 10 km can form, where α is the ballistic coefficient and β is the mass loss parameter. The relevant areas are located at limited values of the β parameter (for small but nonzero values of the α parameter), since a solid body evaporates intensely as it moves in the atmosphere if the β values are sufficiently large. Analysis of the ranges of the α and β variations can help in prediction of catastrophic consequences of entry of cosmic bodies into the Earth’s atmosphere. The values of these parameters should be estimated before impacts with the Earth. The mass and velocity of a body entering the atmosphere seem to be the most difficult to determine a priori. However, precise astronomical observations together with the relevant software will make it possible to cope with this task.
New methods of interpretation of meteor observations were developed and published in 1–9. The interpretation of ground-based observations of meteors and bolides available today in the scientific ...literature all over the world suffers from serious contradictions. Observers use the so-called photometric approach for determination of extra-atmospheric masses of meteoric bodies. This approach is based on the formula proposed in 1933 10 and very simple ideas of how to describe the interaction between the atmospheric air and the surface of a meteoric body. These ideas are provisionally suitable to describe the flow around a body in a free molecular regime. Subsequently, the photometric approach was applied to all the meteor events including bolides. The main effort aimed to elaborate the approach included a choice of new formulas for the radiative efficiency.
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