English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We have conducted a NanoSIMS-based search for presolar material in samplesrecently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2mission. We report the detection of all major presolar grain types with O- andC-anomalous isotopic compositions typically identified in carbonaceouschondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain ofambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of thecarbonaceous grains are presolar graphites, whereas several grains withmoderate C isotopic anomalies are probably organics. The presolar silicate waslocated in a clast with a less altered lithology than the typical extensivelyaqueously altered Ryugu matrix. The matrix-normalized presolar grain abundancesin Ryugu are 4.8$^{+4.7}_{-2.6}$ ppm for O-anomalous grains, 25$^{+6}_{-5}$ ppmfor SiC grains and 11$^{+5}_{-3}$ ppm for carbonaceous grains. Ryugu isisotopically and petrologically similar to carbonaceous Ivuna-type (CI)chondrites. To compare the in situ presolar grain abundances of Ryugu with CIchondrites, we also mapped Ivuna and Orgueil samples and found a total of SiCgrains and 6 carbonaceous grains. No O-anomalous grains were detected. Thematrix-normalized presolar grain abundances in the CI chondrites are similar tothose in Ryugu: 23 $^{+7}_{-6}$ ppm SiC and 9.0$^{+5.3}_{-4.6}$ ppmcarbonaceous grains. Thus, our results provide further evidence in support ofthe Ryugu-CI connection. They also reveal intriguing hints of small-scaleheterogeneities in the Ryugu samples, such as locally distinct degrees ofalteration that allowed the preservation of delicate presolar material.

Presolar stardust in asteroid Ryugu