Gaia FGK benchmark stars: Effective temperatures and surface gravities U. Heiter, P. Jofré, B. Gustafsson, A. J. Korn, C. Soubiran and F. Thévenin A&A, 582 (2015) A49 Published online: 05 October 2015 DOI: 10.1051/0004-6361/201526319