\documentstyle[paasms,pptwocol]{preprint}

\def \um             {\ifmmode \mu \hbox{m}\else $\mu $m\fi }

\input pub.sty

\begin{document}

\title{TITAN'S 5 \protect\boldmath{$\mu$}m SPECTRAL WINDOW:\\
~\\
CARBON MONOXIDE AND THE ALBEDO OF THE SURFACE}

\author{Keith S.~Noll\\
\\
Space Telescope Science Institute\\
3700 San Martin Drive\\
Baltimore, MD 21218\\
phone: 410-338-1828, fax: 410-338-4767, email: noll@stsci.edu\\
\and
Thomas R.~Geballe\\
\\
Joint Astronomy Centre\\
660 N.~A'ohoku Place\\
University Park, Hilo, HI 96720\\
\and
Roger F.~Knacke\\
\\
The Pennsylvania State University\\
Erie, PA 16563\\
\and
Yvonne J.~Pendleton\\
\\
NASA Ames Research Center\\
MS 245-3\\
Moffett Field, CA, 94035} 

\pub{Icarus}
\recacc{7 May 1996}{27 August 1996}
\maketitle

\abstract{
We have measured the spectrum of Titan near 5~\um\ 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~\um\ radiation is reflected from the surface and the mole fraction
of CO in the atmosphere is qCO = 10~${+10\atop -5}$ ppm,
significantly lower than previous estimates for tropospheric CO. The
albedo of the reflecting layer is approximately 0.07~${+0.02\atop
-0.01}$ in the 5~\um\ continuum outside the CO band.  The 5~\um\
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~\um.}