Spectacular fall of the Kendrapara H5 chondrite

Abstract

Abstract-An extremely bright fireball was seen for over 250 km near the eastern coast of India in the evening sky on September 27, 2003. In a rare observation, the fireball was seen by two airline pilots, providing direction of the trail with reasonable accuracy, consistent with ground-based observations. A few fragments of the meteorite were subsequently recovered along the end of the trail in different parts of Kendrapara district (20°30′ N; 86°26′ E) of Orissa. Based on petrography and chemical composition, the meteorite is classified as H5 chondrite. The cosmogenic radionuclides 54 Mn, 22 Na, 60 Co, and 26 Al and tracks have been studied in this stony meteorite. Two of the fragments show an unusually high activity of 60 Co (~160 dpm/kg) indicating a meteoroid radius of 50-150 cm. Assuming that less than 10% (by weight) of the fragments could be recovered because of difficult terrain, an atmospheric mass ablation of >95% is estimated. Based on the observations of the trail and the estimated mass ablation, orbital parameters of the meteoroid have been calculated. The aphelion is found to lie in the asteroidal belt (1.8-2.4 AU), but the inclination of the orbit is large (22°-26°) with respect to the ecliptic. Noble gases have been analysed in two samples of this meteorite. He and Ne are dominantly cosmogenic. Using production rates based on the sample depth derived from 60 Co content, 21 Ne-based exposure age of 4.50 ± 0.45 Ma is derived for Kendrapara. One of the samples, known to be more deeply shielded based on high 60 Co activity, shows the presence of 80 Kr, 82 Kr, and 128 Xe produced by (n, γ) reaction on 79 Br, 81 Br, and 127 I, respectively. The ( 80 Kr/ 82 Kr) n ratio of 3.5 ± 0.9 is consistent with neutrons being mostly thermal. Trapped 84 Kr and 132 Xe are in the expected range for metamorphic grade H5.

Mineral and chemical composition of theJezersko meteorite—A new chondrite fromSlovenia

“…The calculated ratios between refractory lithophile elements and Si, such as Mg/Si (8.12 × 10 −1 ), are in agreement with ratios in H chondrites and also with values in some other reported H chondrites (e.g., Dhingra et al. ; Reimold et al. ).…”

“…As Re and Ru have already been reported to be more susceptible to oxidation and more mobile elements (Palme et al 1998;Horan et al 2003), this could be interpreted as a consequence of the more oxidized character of the Jezersko meteorite parent body. The calculated ratios between refractory lithophile elements and Si, such as Mg/Si (8.12 9 10 À1 ), are in agreement with ratios in H chondrites and also with values in some other reported H chondrites (e.g., Dhingra et al 2004;Reimold et al 2004). Calculated ratios between siderophile and lithophile elements Fe/Mg, Fe/Si, Ir/Mg, and Ir/Si are 1.82, 1.47, 5.06 9 10 À6 , and 4.11 9 10 À6 , respectively.…”

Cosmogenic radioisotopes in the Almahata Sitta ureilite

“…The 22 Na ⁄ 26 Al activity ratio in Almahata Sitta, together with those measured in meteorites which fell during the last four solar cycles. The data are taken from Bhandari et al (1994), Dhingra et al (2004), Shukla et al (2005) and later measurements carried out at the Physical Research Laboratory, India. Calculated activity ratios expected for L and H chondrites are shown by a solid line.…”

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“…9 There were many studies on mineralogical and geochemical characterization of meteorites which fell in India, but there were no reports on spectroscopic studies on meteorites that fell in India were carried out. [10][11][12][13] Raman spectroscopy has already been used for meteorite characterization and identification of shock-induced features, [7][8][9] this paper reports the vibrational characteristics of olivine and pyroxene on the ordinary chondrite and to investigate the presence of any high pressure phase in Kamargaon.…”