An Analysis of the Spectrum of Mars.

On a high-dispersion spectrogram of Mars taken at Mount Wilson rotational lines of 1120 near X 8300 and CO2 near x 8700 have been detected. Recent laboratory measurements of line strengths by D Rank have been used to determine the amounts of H2O and CO2 in the atmosphere of Mars: t4 + 7 precipitable water and 55 + 20 m atm CO2. From the absence of O2 in the Martian spectra, we set an upper limit of 70 cm atm for the O2 content. By suitably combining the CO2 amount with observations by Kuiper and Sinton of the strongly saturated bands in the 2-j# region, a surface pressure of 25 + 15 mb has been derived. The implications of the results on the composition of the Martian atmosphere are discussed.