Infrared spectroscopy of the pulsating Mira variable R Leonis in the region from 1.6 to 2.5 microns is analyzed. Central depths, equivalent widths, and radial velocities are determined for the strong low-excitation lines of the OH first overtones and the CO first and second overtones observed in the spectra. The examined IR spectrum of R Leo is found to be composite, containing lines from two distinct regions of the stellar atmosphere. A 'cool component' is identified with an approximately 1000-K gas layer with a velocity amplitude of about 16 km/s and a mass of no more than 0.001 solar mass; it is suggested that the cool-component lines are likely to originate in a section of the circumstellar shell close to the star. 'Warm-component' lines are shown to have an excitation temperature of approximately 3500 K and a probable origin in the stellar photosphere, which would be characterized by a velocity amplitude of about 35 km/s during the light cycle.
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K. H. Hinkle (1978) studied this question.