Raising the observed metallicity floor with a 3D non-LTE analysis of SDSS J102915.14+172927.9 C. Lagae, A. M. Amarsi, L. F. Rodríguez Díaz, K. Lind, T. Nordlander, T. T. Hansen and A. Heger A&A, 672 (2023) A90 Published online: 05 April 2023 DOI: 10.1051/0004-6361/202245786