Evidence of a primordial isotopic gradient in the inner region of the solar protoplanetary disc J. Mah, R. Brasser, J. M. Y. Woo, A. Bouvier and S. J. Mojzsis A&A, 660 (2022) A36 Published online: 11 April 2022 DOI: 10.1051/0004-6361/202142926