Science Case 2.2 - Methane Spectroscopy: Problem Description
The near-infrared spectrum of Titan, as well as the one of all giant planets, is dominated by strong methane absorption bands. A precise modeling of the atmospheric methane is required in order to analyze the Titan spectra taken by CASSINI/VIMS and Huygens/DISR. It is not easy to obtain because:
- It involves very complex high-energy vibrational polyads.
- The study of transparence windows implies rotationally highly excited levels as well as contributions from the far wings of intense lines.
- A study of the minor isotopologues is needed.
To solve this problem, it is necessary to couple together several approaches:
- Line-by-line analyses.
- New measurements at low temperature and very long optical paths, in order to better simulate Titan's conditions.
- High-quality quantum chemistry calculations combined with new theoretical tools to convert the results into synthetic spectra.
- Theory of lineshapes for methane perturbed by N2 or H2.
| File subject | File format |
|---|---|
| Methane Titan (November 2007) | |
| Methane Spectroscopy (2008) | .ppt |
