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Cluster analysis of presolar silicon carbide grains based on literature datafor 12C/13C, 14N/15N, {\delta}30Si/28Si, and {\delta}29Si/28Si including or notinferred initial 26Al/27Al data, reveals nine clusters agreeing with previouslydefined grain types but also highlighting new divisions. Mainstream grainsreside in three clusters probably representing different parent starmetallicities. One of these clusters has a compact core, with a narrow range ofcomposition, pointing to an enhanced production of SiC grains in asymptoticgiant branch (AGB) stars with a narrow range of masses and metallicities. Theaddition of 26Al/27Al data highlights a cluster of mainstream grains, enrichedin 15N and 26Al, which cannot be explained by current AGB models. We definedtwo AB grain clusters, one with 15N and 26Al excesses, and the other with 14Nand smaller 26Al excesses, in agreement with recent studies. Their definitiondoes not use the solar N isotopic ratio as a divider, and the contour of the26Al-rich AB cluster identified in this study is in better agreement withcore-collapse supernova models. We also found a cluster with a mixture ofputative nova and AB grains, which may have formed in supernova or novaenvironments. X grains make up two clusters, having either strongly correlatedSi isotopic ratios or deviating from the 2/3 slope line in the Si 3-isotopeplot. Finally, most Y and Z grains are jointly clustered, suggesting that theprevious use of 12C/13C= 100 as a divider for Y grains was arbitrary. Ourresults show that cluster analysis is a powerful tool to interpret the data inlight of stellar evolution and nucleosynthesis modelling and highlight the needof more multi-element isotopic data for better classification.

Cluster analysis of presolar silicon carbide grains: evaluation of their classification and astrophysical implications