Geoscience Reference
In-Depth Information
C3H8
1.2
0.9
0.6
C2H6
1.2
0.9
0.6
C2H4
1.2
0.9
0.6
C2H2
1.2
0.9
0.6
3
3.2
3.4
3.8
3.6
Wavelength (micron)
Fig. 2. Modeled spectra including nonmethane hydrocarbons (NMHCs) as the fourth
component. The fourth components are C
2
H
2
,C
2
H
4
,C
2
H
6
,andC
3
H
8
. The model
parameters of the basic ternary mixture are the same as those in Fig. 1, and the mass
fraction to CH
4
of the fourth component is 0.1.
Observation
ternary + C2H6
ternary + C2H6 + C2H2
1
0.8
0.6
0.4
0.2
3
3.2
3.4
3.6
3.8
Wavelength (micron)
Fig. 3. Reflectance spectrum of Pluto with the modeled spectra. The circles show
our observation as shown in Fig. 1. The dashed and dotted curves represent the syn-
thetic spectrum with C
2
H
6
:CH
4
=1:10andC
2
H
2
:C
2
H
6
:CH
4
with mass ratios 1:1:10,
respectively.
comparison with the observed spectrum. In both cases, the observed absorp-
tions around 3.2 and 3.35
ยต
m shifts toward shorter wavelengths compared
with the model spectra. Quirico and Schmitt
8
have shown that the dilution
in solid N
2
ice cause the shift of hydrocarbons' absorptions. More laboratory
experiments are needed to explore the dilution effect more quantitatively.
