Atmospheric Chemistry of Titan Options

[Juramike]

Here is a "Benzene-O-Vision" graphic showing the amount of benzene and phenyl radicals at high altitudes on Titan. This is based on detections of benzene and phenyl radical (which recombined in the sample chamber to make benzene) using the INMS instrument during closest approach. The numbers are normalized to constant pressure altitude, roughly 1000 km.



The data was taken from Table 1 in: Vuitton et al, Journal of Geophysical Research 113 (2008) E05007. "Formation and distribution of benzene on Titan". doi: 10.1029/2007JE002997 [EDIT 5/24/10: Article freely available here] and overlaid on a map of Titan.

The authors mentioned that the errors in these measurements are 20%.

These detections are well above the detached haze layer. Most are at the same sun azimuth angle. (T23 observation had the lowest angle.) Assuming that the temporal difference is minimal (each dot is from a different flyby), there doesn't appear to be an obvious correlation with latitude.

This graphic does show that benzene is present even waaaay up in the thermosphere and ionosphere.

[Juramike]

n-Butane (C4H10) [CH3CH2CH2CH3]



Boring butane comes from the straightforward recombination of two ethyl radicals (which comes primarily from acetylene radical ripping a proton off ethane to make ethyl radical). This happens primarily at very low altitudes.

In an atmosphere without a lot of acetylene photochemistry (H2 or methane-rich atmospheres), ethyl radical can form from C-H cleavage of ethane, but it is a lower efficiency process. So very small amounts of butane should be observed on Jupiter and the other H2 rich gas giants. (Recall that acetylene production requires .:CH, which is a 30% product of electronic recombination of CH3+ and an electron, and CH3+ doesn't form in H2 or methane-rich atmospheres, it forms best with Ar or N2 as a diluant gas, like on Titan)


Next up is the Mac Daddy of Titan's organics - benzene.