History of individual presolar SiC grains revealed by stellar winds.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41087381.
- Also identified by DOI 10.1038/s41467-025-64216-1 and PMC identifier 12521403.
- Licence recorded as CC BY-NC-ND.
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Abstract
Asymptotic giant branch (AGB) stars, which are evolved low- to intermediate-mass stars, rank among the most prolific producers of interstellar dust in the Galaxy. Presolar silicon carbide (SiC) grains in meteorites are mainly produced by AGB stars. These presolar grains contain abundant noble gases, believed to have been implanted by stellar winds from the central stars of planetary nebulae (CSPNe). Here we report 3-D maps of the helium distribution in individual presolar SiC grains. The maps reveal that the implantation energy of <sup>4</sup>He for individual grains varies from about 2 to about 4 keV/nucleon, which falls within the range of the CSPN winds. The variation of <sup>4</sup>He fluence (1×10<sup>12</sup>-2×10<sup>15</sup> atom cm<sup>-2</sup>) shows that the SiC grains form during the last about 1 My period of the AGB star phase. Then, they migrate outwards and become exposed to CSPN winds at distances of 0.3-32 light-years from the CSPNe.