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. 2023 Jul 14;9(28):eadh1003. doi: 10.1126/sciadv.adh1003

Fig. 5. Abundances of presolar grains in Ryugu, carbonaceous chondrites, and an AMM.

Fig. 5.

Abundances of presolar silicates and oxides (O-rich), SiC, and graphite in clasts 1 and 2 and Ryugu matrix compared to abundances in chondrites of various classes [(9) and references therein (10, 18, 19, 22, 33, 36, 37, 51)] and an AMM (31). The abundances in Ryugu are consistent with CI chondrites except for clasts 1 and 2, which have remarkably high abundances of presolar SiC grains. The presolar silicate abundance in clast 1 is similar to primitive chondrites and not altered CI. Presolar O-rich grain abundances for A0040 clast 2, total Ryugu without clasts, and Ivuna (22) are upper limits. Errors are 1σ. wo, without. Not plotted are presolar grain abundances in comet Wild 2 and IDPs. The abundance of O-rich presolar grains in comet Wild 2 samples is 600 to 830 ppm, and the abundance of presolar SiC is 45 ppm (26). Anhydrous IDPs display a wide range of presolar abundances for O-rich grains (20 to 23,080 ppm including 1σ errors) and SiC grains (10 to 630 ppm including 1σ errors) (21, 27, 34, 35).