Cosmogenic radioisotopes in the Almahata Sitta ureilite

Taricco, Carla; Bhandari, N.; Colombetti, P.; Romero, A.; Vivaldo, Gianna; Sinha, N.; Jenniskens, Peter; Shaddad, Muawia H.; Ballabh, G. M.

doi:10.1111/j.1945-5100.2010.01135.x

Cited by 5 publications

(1 citation statement)

References 20 publications

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“…For sample #4, the carbon content was determined by A. Steele (personal communication). Short‐lived radionuclides were measured in the main mass of sample #15 (Taricco et al. 2010).…”

Section: Sample Selection and Experimental Methodsmentioning

confidence: 99%

Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC₃

Welten

Meier

Caffee

et al. 2010

Meteorit & Planetary Scien

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Abstract-On October 7, 2008, a small F-class asteroid, 2008 TC 3 , exploded in Earth's atmosphere, and produced a strewn field of meteorites in the Nubian Desert of Sudan. Subsequent searches yielded several hundred meteorite fragments, known as Almahata Sitta. This fall was classified as a polymict ureilite. We measured cosmogenic radionuclides in six fragments and noble gases in four fragments of the Almahata Sitta ureilite. The concentrations of 10 Be, 26 Al, and 36 Cl in the meteorite fragments of asteroid 2008 TC 3 indicate a preatmospheric radius of 300 ± 30 g cm )2 . Combined with an absolute radius of 1.8 ± 0.2 m, which was derived from its brightness in space, the cosmogenic radionuclides constrain the bulk density of asteroid 2008 TC 3 to 1.66 ± 0.25 g cm )3 and the bulk porosity to 50 ± 7%. The bulk density of asteroid TC 3 is on the low end of the range of 1.6-3.3 g cm )3 determined for 40 of the recovered ureilite fragments. Since the denser materials have a higher chance of surviving atmospheric fragmentation, the lowdensity ureilites are probably more representative of the bulk asteroid. We thus conclude that the high porosity of asteroid 2008 TC 3 is mainly due to microporosity, which implies that not all low-density asteroids are necessarily rubble pile structures. Finally, from the cosmogenic 21 Ne concentrations, we determined a cosmic-ray exposure (CRE) age of 19.5 ± 2.5 Myr. This age represents the time since asteroid 2008 TC 3 was ejected from a large F-class parent body in the asteroid belt, until its collision with Earth.

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“…For sample #4, the carbon content was determined by A. Steele (personal communication). Short‐lived radionuclides were measured in the main mass of sample #15 (Taricco et al. 2010).…”

Section: Sample Selection and Experimental Methodsmentioning

confidence: 99%

Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC₃

Welten

Meier

Caffee

et al. 2010

Meteorit & Planetary Scien

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The Almahata Sitta polymict breccia and the late accretion of asteroid 2008 TC3

2014

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Low γ activity measurement of meteorites using HPGe–NaI detector system

Colombetti

Taricco

Bhandari

et al. 2013

Nuclear Instruments and Methods in Physics Research Section A:

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The radioactivity in natural samples like cosmogenic isotopes in meteorites, in Moon samples, in earth and ice in Antarctica, produced by protons, neutrons, μμ mesons and other charged particles, is very low, usually below 0.001 disintegration per minute per gram. Therefore, very special techniques are required, particularly if the sample cannot be destroyed for chemical separation and system must have possibility of counting large amount of sample. For this purpose we have developed a highly selective Ge-NaI coincidence spectrometer, operating in the underground Laboratory of Monte dei Cappuccini (INAF) in Torino. We have then improved it by developing a multiparametric acquisition system, which allows better selectivity of the coincidence windows (e.g., in meteorites, to disentangle cosmogenic 44 Ti signal from overlapping 214 Bi, originated by naturally occurring 238 U). Applications of this system to the study of meteorites (chondrite, achondrite and iron samples) are described.

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Cosmogenic radioisotopes in the Almahata Sitta ureilite

Cited by 5 publications

References 20 publications

Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC₃

Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC₃

The Almahata Sitta polymict breccia and the late accretion of asteroid 2008 TC3

Low γ activity measurement of meteorites using HPGe–NaI detector system

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Cosmogenic radioisotopes in the Almahata Sitta ureilite

Cited by 5 publications

References 20 publications

Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC3

Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC3

The Almahata Sitta polymict breccia and the late accretion of asteroid 2008 TC3

Low γ activity measurement of meteorites using HPGe–NaI detector system

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Product

Resources

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Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC₃

Cosmogenic nuclides in Almahata Sitta ureilites: Cosmic‐ray exposure age, preatmospheric mass, and bulk density of asteroid 2008 TC₃