Igneous meteorites suggest Aluminium-26 heterogeneity in the early Solar Nebula
Evgenii Krestianinov, Yuri Amelin, Qing‐Zhu Yin, Paige Cary, Magdalena H. Huyskens, Audrey Miller, S. Dey, Yuki Hibiya, Haolan Tang, Edward Young, Andreas Pack, Tommaso Di Rocco
Abstract
Abstract The short-lived radionuclide aluminium-26 ( 26 Al) isotope is a major heat source for early planetary melting. The aluminium-26 – magnesium-26 ( 26 Al- 26 Mg) decay system also serves as a high-resolution relative chronometer. In both cases, however, it is critical to establish whether 26 Al was homogeneously or heterogeneously distributed throughout the solar nebula. Here we report a precise lead-207 – lead-206 ( 207 Pb- 206 Pb) isotopic age of 4565.56 ± 0.12 million years (Ma) for the andesitic achondrite Erg Chech 002. Our analysis, in conjunction with published 26 Al- 26 Mg data, reveals that the initial 26 Al/ 27 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 26 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.