CO 4.6 micron emission lines from the IRC +10216 inner envelope

Results are presented of an investigation of gas in the inner envelope of IRC +10216 at a scale size (approximately 2 arcsec) never observed previously. Observations were made at the 4.6-micrometer fundamental vibration-rotation band of CO, employing an annular observing aperture to isolate radiation resonantly scattered from the extended molecular envelope. In addition to the expected emission up to the expansion velocity of the envelope, both CO and 13CO show evidence of high-velocity features in the blue wing of the line, beyond the 15 km/s expansion velocity. A mass loss rate for the inner envelope of approximately 5-7 x 10 to the -5 solar mass per year is derived (lower than the values derived for the extended envelope from millimeter CO data).