Material Property Database of Organic Liquids, Ices, and Hazes on Titan

Titan has a diverse range of materials in its atmosphere and on its surface: the simple organics that reside in various phases (gas, liquid, ice) and the solid complex refractory organics that form Titan’s haze layers.

These materials all actively participate in various physical processes on Titan, and many material properties are found to be important in shaping these processes. Future in-situ exploration on Titan would likely encounter a range of materials, and a comprehensive database to archive the material properties of all possible material candidates will be needed.

Here we summarize several important material properties of the organic liquids, ices, and the refractory hazes on Titan that are available in the literature and/or that we have computed. For the simple organics, we include 18 species that are detected by Cassini/ground-based telescopes: CH₄, C₂H₆, C₂H₄, C₂H₂, C₄H₂, C₆H₆, C₃H₈, C₃H₆, C₃H₄-a (allene), C₃H₄-p (propyne), HCN, HC₃N, CO₂, CH₃CN, C₂H₅CN, C₂H₃CN, C₂N₂, C₄N_2. For the complex organics, we include measured properties of Titan haze analogs (“tholins”) from 6 laboratories.

The properties include thermodynamic proper****ties (phase change points, sublimation saturation vapor pressure (sublimation SVP), vaporization saturation vapor pressure (vaporization SVP), and sublimation and vaporization latent heat), physical properties (organic liquid density, organic ice density, and haze density), and surface properties (organic liquid surface tension, organic ice surface energy, and haze surface energy). These data can be used as inputs for various theoretical models to interpret current and future remote sensing and in-situ atmospheric and surface measurements on Titan. The material properties of the simple organics may also be applicable to giant planets and icy bodies in the outer solar system, exoplanets, interstellar medium, and protoplanetary disks.