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Presolar diamond, the carrier of the isotopically anomalous Xe component Xe-HL, was the first mineral type of presolar dust that was isolated from meteorites. The excesses in the light, p-process only isotopes 124Xe and 126Xe, and in the heavy, r-process only isotopes 134Xe and 136Xe relative to the solar ratios indicate that Xe-HL was produced in supernovae: they are the only stellar source where these two processes are believed to take place. Although these processes occur in supernovae, their physical conditions and timeframes are completely different. Yet the excesses are always correlated in diamond separates from meteorites. Furthermore, the p-process 124Xe/126Xe inferred from Xe-L and the r-process 134Xe/136Xe from Xe-H do not agree with the p-process and r-process ratios derived from the solar system abundance, and the inferred p-process ratio does not agree with those predicted from stellar models. The rapid separation scenario, where the separation of Xe and its radiogenic precursors Te and I takes place at the very early stage (7900 sec after the end of the r-process), has been proposed to explain Xe-H. Alternatively, mixing of 20% of material that experienced neutron burst and 80% of solar material can reproduce the pattern of Xe-H, although Xe-L is not accounted for with this scenario.
The main carrier of primordial heavy noble gases in chondrites is thought to be an organic phase, known as phase Q, whose precise characterization has resisted decades of investigation. Indirect techniques have revealed that phase Q might be composed
On the 27th of November 2015, at 10:43:45.526 UTC, a fireball was observed across South Australia by ten Desert Fireball Network observatories lasting 6.1 s. A $sim37$ kg meteoroid entered the atmosphere with a speed of 13.68$pm0.09,mbox{km s}^{-1}$
How simple organic matter appeared on Earth and the processes by which it transformed into more evolved organic compounds, which ultimately led to the emergence of life, is still an open topic. Different scenarios have been proposed, the main one ass
We report a NanoSIMS search for presolar grains in the CM chondrites Asuka (A) 12169 and A12236. We found 90 presolar O-rich grains and 25 SiC grains in A12169, giving matrix-normalized abundances of 275 (+55/-50, 1$sigma$) ppm or, excluding an unusu
The recovery of freshly fallen meteorites from tracked and triangulated meteors is critical to determining their source asteroid families. However, locating meteorite fragments in strewn fields remains a challenge with very few meteorites being recov