All available spectra of the M1.5 V star GJ 2. Top: region around the He I IR line. Some artefacts of airglow and cosmics manifest themselves as emission spikes. Middle: region around Hα. Minor telluric contamination at about 6559–6560 and 6566–6567 Å is evident. The dashed vertical lines indicate the central wavelength of the He I IR and Hα lines, respectively. Bottom: correlation for different chromospheric lines to pEW(Hα). Black denotes pEW(He I IR), blue denotes pEW(He I D₃) scaled by −4, and red denotes pEW(Ca II IRT₁) scaled by 0.5.