Spectral region around the He I IRT lines. Shown are the CARMENES spectrum (black) and a PHOENIX purely photospheric comparison spectrum (red). We additionally show two possible models with a Gaussian shaped emission and absorption added to the PHOENIX spectrum (cyan and magenta). The vertical dashed lines mark the position of a Si I line at 10830.057 Å, and the three components of the He I IRT. The narrow emission line is an OH airglow line, while the three narrow absorption lines are telluric lines.