Detection of the 1.6 μm E 4Π-A 4Π FEH system in sunspot and cool star spectra

Lines of a previously undescribed molecular band have been identified in high-resolution spectra of sunspots and in the spectra of two M dwarfs and one L dwarf. This band has also been found in laboratory spectra of a source known to produce FeH. The band has a head at 1.583 mum (6317 cm(-1)) and is degraded to longer wavelengths. Based on observational evidence and a published predicted band position, it is suggested that this is the 0-0 band of the E (4)Pi -A (4)Pi system of FeH.