Igneous meteorites suggest Aluminium-26 heterogeneity in the early Solar Nebula.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37643999.
- Also identified by DOI 10.1038/s41467-023-40026-1 and PMC identifier 10465487.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The short-lived radionuclide aluminium-26 (<sup>26</sup>Al) isotope is a major heat source for early planetary melting. The aluminium-26 - magnesium-26 (<sup>26</sup>Al-<sup>26</sup>Mg) decay system also serves as a high-resolution relative chronometer. In both cases, however, it is critical to establish whether <sup>26</sup>Al was homogeneously or heterogeneously distributed throughout the solar nebula. Here we report a precise lead-207 - lead-206 (<sup>207</sup>Pb-<sup>206</sup>Pb) isotopic age of 4565.56 ± 0.12 million years (Ma) for the andesitic achondrite Erg Chech 002. Our analysis, in conjunction with published <sup>26</sup>Al-<sup>26</sup>Mg data, reveals that the initial <sup>26</sup>Al/<sup>27</sup>Al in the source material of this achondrite was notably higher than in various other well-preserved and precisely dated achondrites. Here we demonstrate that the current data clearly indicate spatial heterogeneity of <sup>26</sup>Al by a factor of 3-4 in the precursor molecular cloud or the protoplanetary disk of the Solar System, likely associated with the late infall of stellar materials with freshly synthesized radionuclides.