Titan's 5 micrometers spectral window:  carbon monoxide and the albedo of the surface.
We have measured the spectrum of Titan near 5 micrometers and have found it to be dominated by absorption from the carbon monoxide 1-0 vibration-rotation band. The position of the band edge allows us to constrain the abundance of CO in the atmosphere and/or the location of the reflecting layer in the atmosphere. In the most likely case, 5 micrometers radiation is reflected from the surface and the mole fraction of CO in the atmosphere is qCO=10(+10/-5) ppm, significantly lower than previous estimates for tropospheric CO. The albedo of the reflecting layer is approximately 0.07(+0.02/-0.01) in the 5 micrometers continuum outside the CO band. The 5 micrometers albedo is consistent with a surface of mixed ice and silicates similar to the icy Galilean satellites. Organic solids formed in simulated Titan conditions can also produce similar albedos at 5 micrometers.
Noll
K S
KS
Space Telescope Science Institute, Baltimore, Maryland 21218, USA.  noll@stsci.edu
Geballe
T R
TR
Knacke
R F
RF
Pendleton
Y J
YJ
D055580:Astronomical Phenomena; D001256:Astronomy; D001272:Atmosphere / Q000032:analysis*; D002248:Carbon Monoxide; D005118:Extraterrestrial Environment; D010783:Photometry; D018539:Saturn; D013057:Spectrum Analysis
D002248:Carbon Monoxide