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|Gardiol, D., Barghini, D., Buzzoni, A., Carbognani, A., Di Carlo, M., Di Martino, M., Knapic, C., Londero, E., Pratesi, G., Rasetti, S., Riva, W., Salerno, R., Stirpe, G. M., Valsecchi, G. B., Volpicelli, C. A., Zorba, S., Colas, F., Zanda, B., Bouley, S., Jeanne, S. Malgoyre, A., Birlan, M., Blanpain, C., Gattacceca, J., Lecubin, J., Marmo, C., Rault, J. L., Vaubaillon, J., Vernazza, P., Affaticati, F., Albani, M., Andreis, A., Ascione, G., Avoscan, T., Bacci, P., Baldini, R., Balestrero, A., Basso, S., Bellitto, R., Belluso, M., Benna, C., Bernardi, F., Bertaina, M. E., Betti, L., Bonino, R., Boros, K., Bussi, A., Carli, C., Carriero, T., Cascone, E., Cattaneo, C., Cellino, A., Colombetti, P., Colombi, E., Costa, M., Cremonese, G., Cricchio, D., D'Agostino, G., D'Elia, M., De Maio, M., Demaria, P., Di Dato, A., Di Luca, R., Federici, F., Gagliarducci, V., Gerardi, A., Giuli, G., Guidetti, D., Interrante, G., Lazzarin, M., Lera, S., Leto, G., Licchelli, D., Lippolis, F., Manca, F., Mancuso, S., Mannucci, F., Masi, R., Masiero, S., Meucci, S., Misiano, A., Moggi Cecchi, V., Molinari, E., Monari, J., Montemaggi, M., Montesarchio, M., Monti, G., Morini, P., Nastasi, A., Pace, E., Pardini, R., Pavone, M., Pegoraro, A., Pietronave, S., Pisanu, T., Pugno, N., Repetti, U., Rigoni, M., Rizzi, N., Romeni, C., Romeo, M., Rubinetti, S., Russo, P., Salvati, F., Selvestrel, D., Serra, R., Simoncelli, C., Smareglia, R., Soldi, M., Stanga, R., Strafella, F., Suvieri, M., Taricco, C., Tigani Sava, G., Tombelli, M., Trivero, P., Umbriaco, G., Vairetti, R., Valente, G., Volpini, P., Zagarella, R. & Zollo, A.:|
|"Cavezzo, the first Italian meteorite recovered by the PRISMA fireball network.
Orbit, trajectory, and strewn-field"|
2021, Monthly Notices of the Royal Astronomical Society, 501, 1215
Two meteorite pieces have been recovered in Italy, near the town of Cavezzo (Modena), on 2020 January 4th. The associated fireball was observed on the evening of New Year’s Day 2020 by eight all-sky cameras of the PRISMA fireball network, a partner of FRIPON. The computed trajectory had an inclination angle of approximately 68o and a velocity at infinity of 12.8 km/s. Together with the relatively low terminal height, estimated as 21.5 km, those values were indicating the significant possibility of a meteorite dropping event, as additionally confirmed by the non-zero residual total mass. The strewn-field was computed taking into account the presence of two bright light flashes, revealing that the meteoroid had been very likely subject to fragmentation. Three days after the event, two samples, weighing 3.1 and 52.2 g, were collected as a result of a dedicated field search and thanks to the involvement of the local people. The two pieces were immediately recognized as freshly fallen fragments of meteorite. The computed orbital elements, compared with the ones of known Near-Earth Asteroids from the NEODyS database, are compatible with one asteroid only; 2013 VC10. The estimated original mass of the meteoroid, 3.5 kg, and size, approximately 13 cm, is so far the smallest among the current 35 cases in which meteorites were recovered from precise strewn-field computation thanks to observational data. This result demonstrates the effectiveness of accurate processing of fireball network data even on challenging events generated by small size meteoroids.
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|Figure 1 - |
The two recovered samples of the Cavezzo meteorite. On the right-hand side, the first recovered fragment (F1, 3.1 g); on the left-hand side, the second and larger one (F2, 52.2 g).
|Figure 2 - |
Details of the larger fragment F2 of the Cavezzo meteorite. (a) White streaks occur on one edge of F2, suggesting on-ground breakup of the original body; (b) photomosaic of polarizing optical microscope images (transmitted light, crossed polars) of a thin sections obtained from F2 (field width 12?mm) showing chondrules and chondrule fragments distributed in the matrix.
|Figure 3 - |
Map of the PRISMA stations (white dots) involved in the detection of the IT20200101 fireball. The red line plots the fireball bright trajectory projected on the ground, and white circles enclose the fireball trail seen by each camera (reconstructed from video records). Please notice that fireball trails are oriented accordingly to the specific in-situ hardware installation, and may be not strictly consistent with one another (all-sky images, from which meteor trails are cropped, were approximately oriented with N direction upward and E direction rightward). Background map was generated using the Matplotlib Basemap Toolkit (Hunter 2007).
|Figure 4 - |
Results of trajectory computation and dynamical model for the IT20200101 fireball. (a) Vertical projection of the atmospheric trajectory; (b) vertical residuals of the atmospheric trajectory; (c) fireball velocity with respect to ground; (d) aerodynamic pressure (Equation 1); (e) absolute magnitude (at 100 km, zenith of the observer). The x-axis reports the time elapsed from the beginning of the visible flight captured by the eight cameras. The two vertical dashed lines indicate the times at which the two flares occurred, 3.95 and 4.15 s, respectively. In every panel, grey points plot measured or computed values for the single stations, whereas the red line plots the nominal fit values (a–c) or a smoothed version of grey points (d,e). Red shaded area encloses 1σ uncertainty.
|Figure 5 - |
Wind vertical profile at 18 UTC in the Cavezzo area used for the strewn-field computation. The red arrow shows the fireball motion direction on the ground.
|Figure 6 - |
Strewn-field for the Cavezzo meteorite fragments, as a function of different mass-section ratio values (D, dashed black lines) from 30 up to 200 kg/m2. The brown thick line shows the nominal impact point and the shaded areas enclose 1σ (red), 2σ (orange), and 3σ (yellow) uncertainties in the transverse direction. The purple star shows where the two Cavezzo fragments F1 and F2 were recovered, and the thick red line plots the terminal part of the bright flight trajectory, projected on the ground. Background map data copyright of OpenStreetMap.
|Figure 7 - |
The reconstructed heliocentric orbit for the progenitor meteoroid of the Cavezzo meteorite (red ellipse) as seen from the ecliptic north pole and projected on to the ecliptic plane, together with the 1s uncertainty band (shaded red area). The blue ellipse plots the 2013 VC10 orbit (for which orbital elements are provided by the NEODyS data base). Remaining ellipses plot Solar system planets’ orbits up to Jupiter, and the black dots indicate their position along the orbit at the time of the IT20200101 fireball. The black small dots symbolically represent the asteroid Main Belt.
|Figure 8 - |
The radiants of the Cavezzo meteoroid (red dot) and of 2013 VC10 (cyan dot) in an equal area projection of the sky centred on the apex of the Earth motion (a) and on the opposition (b); the angular coordinates are ecliptic longitude minus the longitude of the Sun, and ecliptic latitude. The orange dots are the radiants of the simulated impactors of Chesley & Spahr (2004), while the black dots are the radiants of the 20 meteorites listed in Granvik & Brown (2018).
|Table 1 - |
List and relevant data of ‘pedigree’ meteorites, i.e. for which recovery was accompanied by a sufficient set of sporadic or systematic observations (optical, radio, infrasound, seismic, satellite), allowing for pre-impact orbit reconstruction. From left- to right-hand side: name of the meteorite (approved by The Meteoritical Society), date of fall, pre-atmospheric velocity and mass, estimated terminal mass, meteorite total known weight (TKW) recovered on the ground, minimum absolute magnitude recorded, impact energy (equivalent tons of TNT, 1 T = 4.187 × 109 J), fireball network which provided the observations (if any) and references for table data. The uncertainties associated to the values of the table are not given here for simplicity, but can be found in the respective references.
|Table 2 - |
PRISMA stations that observed the IT20200101 fireball. From left to right: station name, latitude, longitude, and elevation above sea level.
|Table 3 - |
IT20200101 fireball parameters obtained from triangulation and dynamical model. The two columns refer to values at the beginning and end of the bright flight, respectively (when applicable). Values of mass and diameter are computed from the mass-section ratio D (in the hypothesis of pure ablation) by assuming a spherical shape of the meteoroid and for the measured meteorite bulk density of 3.322 g/cm-3.
|Table 4 - |
Data regarding the nominal impact points with different D final values. From top to bottom: final mass-section value, latitude and longitude of the impact point, shift parallel (L) and orthogonal (X) to motion direction of the bright flight and on-ground impact velocity.
|Table 5 - |
Orbital elements (top) and proper elements (bottom) of the Cavezzo meteoroid (left) and of 2013 VC10 from NEODyS (right).
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