Correction to: Nature https://doi.org/10.1038/s41586-025-09361-9 Published online 3 September 2025

In the version of the article initially published, in the “Composition of the Martian core” section of the Methods, the text “The influence of O, C and S on the OC velocity and density are calculated as follows” incorrectly included a citation to ref. 54 which has now been replaced with ref. 70 (Huang, D. et al. Thermoelastic properties of liquid Fe-rich alloys under martian core conditions. Geophys. Res. Lett. 50, e2022GL102271 (2023)) in the HTML and PDF versions of the article.