AlH lines in the blue spectrum of Proxima Centauri

ABSTRACT The recently computed ExoMol line lists for isotopologues of AlH are used to analyse the blue spectrum (4000–4500 Å) Proxima Cen (M5.5 V). Comparison observed and spectra enables identification a large number 27AlH lines A 1? –X 1?+ band system: spectral range covering 1-0, 0-0, 1-1 bands dominated by clearly resolved lines. We reveal diffuse nature transitions close dissociation limit which appears in form increasingly wider (up 5 shallower continuum confusion limit) profiles. predicted wavelengths systematically displaced. effect broadening predissociation states on profiles is included increasing radiative damping rate up orders magnitude. determine empirical values rates clean 0-0 Q-branch comparing synthetic stellar spectra. find excellent agreement between our lifetimes available literature. comparison 27Al1H REALH shows that better described list. search 26Al1H does not any notable features; giving an upper /26Al1H >100.