K2-106, a system containing a metal-rich planet and a planet of lower density E. W. Guenther, O. Barragán, F. Dai, D. Gandolfi, T. Hirano, M. Fridlund, L. Fossati, A. Chau, R. Helled, J. Korth et al. (36 more) A&A, 608 (2017) A93 Published online: 11 December 2017 DOI: 10.1051/0004-6361/201730885