The reflectivity spectrum of Mars in the near-infrared☆

Abstract Spectral scans have been obtained of Mars and a region on the Moon in the range 0.5 μ to 1.2 μ at the 82-inch telescope. These have been reduced, with the aid of scans of the Moon and the Sun, to a spectral reflectivity curve. Published data have allowed an extrapolation to 1.52 μ. The monochromatic Russell-Bond albedo is found to rise to a maximum if 39% at 0.84 μ. A shallow minimum occurs near 1 μ, followed by a rise to 49% at 1.52 μ. Apparently the albedo is still rising at 1.52 μ. The radiometric albedo is found to be 0.287. Earlier conclusions that the surface layer of Mars consists largely of limonite are not inconsistent with these observations, as indicated by laboratory reflectivity spectra.