The fall of the Grimsby meteorite—I: Fireball dynamics and orbit from radar, video, and infrasound records

Abstract-The Ko sice meteorite fall occurred in eastern Slovakia on February 28, 2010, 22:25 UT. The very bright bolide was imaged by three security video cameras from Hungary. Detailed bolide light curves were obtained through clouds by radiometers on seven cameras of the European Fireball Network. Records of sonic waves were found on six seismic and four infrasonic stations. An atmospheric dust cloud was observed the next morning before sunrise. After careful calibration, the video records were used to compute the bolide trajectory and velocity. The meteoroid, of estimated mass of 3500 kg, entered the atmosphere with a velocity of 15 km s À1 on a trajectory with a slope of 60°to the horizontal. The largest fragment ceased to be visible at a height of 17 km, where it was decelerated to 4.5 km s À1 . A maximum brightness of absolute stellar magnitude about À18 was reached at a height of 36 km. We developed a detailed model of meteoroid atmospheric fragmentation to fit the observed light curve and deceleration. We found that Ko sice was a weak meteoroid, which started to fragment under the dynamic pressure of only 0.1 MPa and fragmented heavily under 1 MPa. In total, 78 meteorites were recovered in the predicted fall area during official searches. Other meteorites were found by private collectors. Known meteorite masses ranged from 0.56 g to 2.37 kg. The meteorites were classified as ordinary chondrites of type H5 and shock stage S3. The heliocentric orbit had a relatively large semimajor axis of 2.7 AU and aphelion distance of 4.5 AE 0.5 AU. Backward numerical integration of the preimpact orbit indicates possible large variations of the orbital elements in the past due to resonances with Jupiter.

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“… and table 1 of Brown et al. and Spurný et al. ); the second largest being Park Forest with 4.26 ± 0.38 AU (Brown et al.…”

Section: The Preatmospheric Orbitmentioning

confidence: 94%

“…That number has grown rapidly in the recent years, totaling approximately 15 as of 2011 (for detailed descriptions of some recent cases, see Brown et al. ; Spurný et al. , ).…”

Section: Introductionmentioning

confidence: 99%

The Košice meteorite fall: Atmospheric trajectory, fragmentation, and orbit

Borovička

Tóth

Igaz

et al. 2013

Meteorit & Planetary Scien

106

120

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“…for the Chelyabinsk airburst, based on indirect illumination measured from video records. The brightness is an average derived from indirect scattered sky brightness from six videos proximal to the airburst, corrected for the sensor gamma setting, autogain, range and airmass extinction, following the procedure used for other airburst light curves generated from video 24,25 . The light curve has been normalized using the US government sensor data peak brightness value of 2.7 3 10 13 W sr…”

mentioning

confidence: 99%

A 500-kiloton airburst over Chelyabinsk and an enhanced hazard from small impactors

Brown

Assink

Astiz

et al. 2013

Nature

Self Cite

380

308

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Most large (over a kilometre in diameter) near-Earth asteroids are now known, but recognition that airbursts (or fireballs resulting from nuclear-weapon-sized detonations of meteoroids in the atmosphere) have the potential to do greater damage 1 than previously thought has shifted an increasing portion of the residual impact risk (the risk of impact from an unknown object) to smaller objects 2 . Above the threshold size of impactor at which the atmosphere absorbs sufficient energy to prevent a ground impact, most of the damage is thought to be caused by the airburst shock wave 3 , but owing to lack of observations this is uncertain 4,5 . Here we report an analysis of the damage from the airburst of an asteroid about 19 metres (17 to 20 metres) in diameter southeast of Chelyabinsk, Russia, on 15 February 2013, estimated to have an energy equivalent of approximately 500 (6100) kilotons of trinitrotoluene (TNT, where 1 kiloton of TNT 54.185310 12 joules). We show that a widely referenced technique 4-6 of estimating airburst damage does not reproduce the observations, and that the mathematical relations 7 based on the effects of nuclear weapons-almost always used with this technique-overestimate blast damage. This suggests that earlier damage estimates 5,6 near the threshold impactor size are too high. We performed a global survey of airbursts of a kiloton or more (including Chelyabinsk), and find that the number of impactors with diameters of tens of metres may be an order of magnitude higher than estimates based on other techniques 8,9 . This suggests a non-equilibrium (if the population were in a long-term collisional steady state the size-frequency distribution would either follow a single power law or there must be a size-dependent bias in other surveys) in the near-Earth asteroid population for objects 10 to 50 metres in diameter, and shifts more of the residual impact risk to these sizes. for the Chelyabinsk airburst, based on indirect illumination measured from video records. The brightness is an average derived from indirect scattered sky brightness from six videos proximal to the airburst, corrected for the sensor gamma setting, autogain, range and airmass extinction, following the procedure used for other airburst light curves generated from video 24,25 . The light curve has been normalized using the US government sensor data peak brightness value of 2.7 3 10 13 W sr 21, corresponding to an absolute astronomical magnitude of 228 in the silicon bandpass. The individual video light curves deviate by less than one magnitude between times 22 and 11.5 with larger deviations outside this interval. Time zero corresponds to 03:20:32.2 UTC on 15 February 2013. b, The energy deposition per unit height for the Chelyabinsk airburst, based on video data. The conversion to absolute energy deposition per unit path length assumes a blackbody emission of 6,000 K and bolometric efficiency of 17%, the same as the assumptions used to convert earlier US government sensor information to energy 26 . The heights are computed us...

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“…The software can output a meteoroid's pre-impact orbit, perform an analysis of the orbital motion of the meteoroid prior to the impact with the Earth, and possibly assist in the identification of the origin or the parent body of the meteoroid. The software also makes it possible to estimate a probable location of the meteorite's fall site (when applicable) by following the numerical integration of the equations of motion (Brown P., et al, 2011) to the intersection with the surface of the Earth. Table 2 presents selected results derived by using the Meteor Toolkit software (labeled "This study" in Table 2).…”

Section: Resultsmentioning

confidence: 99%

“…Buzzard Coulee (Milley, 2010) Grimsby (Brown P., et al, 2011) Neuschwanstein (Spurny, Oberst, & Heinlein, 2003) Sutter's Mill (Jenniskens P. et al, 2012) Chelyabinsk (Popova, O.P., Jenniskens, P. et al, 2013) Košice (Borovicka J., et al, 2013) Meteor Toolkit is an executable file along with some additional dependent libraries. Also note, although Meteor Toolkit uses SPICE libraries and subroutines, they do not need to be compiled as they are assembled into a portable dll.…”

Section: Namementioning

confidence: 99%

Orbit determination based on meteor observations using numerical integration of equations of motion

Dmitriev

Lupovka

Gritsevich

2015

Planetary and Space Science

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Orbit determination based on meteor observations using numerical integration of equations of motion Dmitriev, Vasily Dmitriev , V , Lupovka , V & Gritsevich , M 2015 , ' Orbit determination based on meteor observations using numerical integration of equations of motion ' , Planetary and Space Science , vol. 117 , AbstractRecently, there has been a worldwide proliferation of instruments and networks dedicated to observing meteors, including international airborne campaigns (Vaubaillon, J. et al., 2015) and possible future space-based monitoring systems (Bouquet A., et al., 2014). There has been a corresponding rapid rise in high quality data accumulating annually. In this paper, we present a method embodied in a software program, which can effectively and accurately process these data in an automated mode and discover the pre-impact orbit and possibly the origin or parent body of a meteoroid or asteroid. The required input parameters are the topocentric pre-atmospheric velocity vector and the coordinates of the atmospheric entry point of the meteoroid, i.e. the beginning point of visual path of a meteor, in the an Earth centered-Earth fixed coordinate system, the International Terrestrial Reference Frame (ITRF). Our method is based on strict coordinate transformation from the ITRF to an inertial reference frame and on numerical integration of the equations of motion for a perturbed two-body problem. Basic accelerations perturbing a meteoroid's orbit and their influence on the orbital elements are also studied and demonstrated. Our method is then compared with several published studies that utilized variations of a traditional analytical technique, the zenith attraction method, which corrects for the direction of the meteor's trajectory and its apparent velocity due to Earth's gravity. We then demonstrate the proposed technique on new observational data obtained from the Finnish Fireball Network (FFN) as well as on simulated data. In addition, we propose a method of analysis of error propagation, based on general rule of covariance transformation.

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The fall of the Grimsby meteorite—I: Fireball dynamics and orbit from radar, video, and infrasound records

Cited by 62 publications

References 44 publications

The Košice meteorite fall: Atmospheric trajectory, fragmentation, and orbit

The Košice meteorite fall: Atmospheric trajectory, fragmentation, and orbit

A 500-kiloton airburst over Chelyabinsk and an enhanced hazard from small impactors

Orbit determination based on meteor observations using numerical integration of equations of motion

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