The spectrum of the planetary nebula Ic 4997 in the near infrared range

The absolute intensities of 22 emission lines have been measured in the spectral region lambda=6,300 to 11,000 A. From the (SII) and HI lines the interstellar absorption has been estimated to be Asub(β)=1sup(m)x35. The distribution of energy in the continuous spectrum of the nucleus and in the nebula has been obtained in absolute units. The theoretical spectrum of the nebula has been calculated in the range from lambda=3,000 A to radio frequencies. When calibrated, it lies above the radiocontinuum. It may agree satisfactorily with the radio-observations available if one assumes that IC 4997 becomes optically dense at lambdaapproximately2 cm