Composition, seasonal change, and bathymetry of Ligeia Mare, Titan, derived from its microwave thermal emission
Le Gall, A; Malaska, J; Lorenz, D; Janssen, A; Tokano, T; Hayes, G; Mastrogiuseppe, M; Lunine, I; Veyssiere, G; Encrenaz, P; Karatekin, O. (2016). Composition, seasonal change, and bathymetry of Ligeia Mare, Titan, derived from its microwave thermal emission. J. Geophys. Res. 121(2): 233-251. dx.doi.org/10.1002/2015JE004920 In: Journal of Geophysical Research. American Geophysical Union: Richmond. ISSN 0148-0227; e-ISSN 2156-2202, more |  |
| Author keywords | Titan; radiometry; surface; composition; lakes |
| Authors | | Top | - Le Gall, A
- Malaska, J
- Lorenz, D
- Janssen, A
| - Tokano, T
- Hayes, G
- Mastrogiuseppe, M
- Lunine, I
| - Veyssiere, G
- Encrenaz, P
- Karatekin, O., more
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| Abstract | For the last decade, the passive radiometer incorporated in the Cassini RADAR has recorded the 2.2cm wavelength thermal emission from Titan's seas. In this paper, we analyze the radiometry observations collected from February 2007 to January 2015 over one of these seas, Ligeia Mare, with the goal of providing constraints on its composition, bathymetry, and dynamics. In light of the depth profile obtained by Mastrogiuseppe et al. (2014) and of a two-layer model, we find that the dielectric constant of the sea liquid is <1.8, and its loss tangent is 3.6-2.1+4.3x10-5. Both results point to a composition dominated by liquid methane rather than ethane. A high methane concentration suggests that Ligeia Mare is primarily fed by methane-rich precipitation and/or ethane has been removed from it (e.g., by crustal interaction). Our result on the dielectric constant of the seafloor is less constraining |
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