We observed the near infrared emission in the wavelength range 2.28–2.5 \mu m from the peculiar B [ e ] -star MWC 349 .
The spectra contain besides the strong IR continuum the first overtone CO bands and most of the hydrogen recombination lines of the Pfund series , both in emission .
We also modeled the spectra .
The Pfund lines have a gaussian profile with a FWHM of \sim 100 km/s , and it turned out that their emission is in LTE and optically thin .
To explain the CO bands , several scenarios were investigated .
We found that the CO band heads are formed under LTE and that the gas must have a temperature of 3500 to 4000 K. The width of the 2 \rightarrow 0 band head indicates kinematical broadening of 50 to 60 km/s .
We can obtain fits to the measured spectra assuming that the CO gas has a column density of 5 \cdot 10 ^ { 20 } cm ^ { -2 } and is located either at the inner edge of the rotating circumstellar disk .
In this case , the disk must have a bulge which partly blocks the radiation so that the observer sees only a sector on the far side where the radial velocities are small .
Or the CO emission originates in a wind with gaussian line profiles .
Both fits are of equal quality and satisfactory .
In a third alternative where the fit is less convincing , the CO emission is optically thin and comes from an extended Keplerian disk .