Systematic trend of water vapour absorption in red giant atmospheres revealed by high resolution TEXES 12 μm spectraN. Ryde, J. Lambert, M. Farzone, M. J. Richter, E. Josselin, G. M. Harper, K. Eriksson and T. K. GreathouseA&A, 573 (2015) A28DOI: https://doi.org/10.1051/0004-6361/201424851