A standard stellar spectral sequence in the red/near-infrared: Classes K5 to M9

Spectra of 39 K and M dwarf spectroscopic standards, as well as 38 secondary standards, are shown from 6300 to 9000 Å. This sequence of 77 spectra ranges from K5 V to M9 and has been classified on the Boeshaar system. Spectra of 14 giant and higher luminosity stars are presented from 6900 to 9000 Å, along with two miscellaneous spectra. Also given is an extensive list of atomic and molecular features found in the spectra of late K and M stars of all luminosity classes. From the spectral slopes and the strengths of the red/near-infrared spectral features it is possible to distinguish giants from dwarfs and to classify M dwarfs of all spectral subclasses. The library of spectra has been used to construct a spectral class versus mass relation which allows mass estimates to be made based upon a dwarf's spectral class alone. The relation is based on eight objects having both well-determined masses and spectral types.