The opening workshop in July 2015 addressed non-aqueous environments that meet the overall requirements for habitability (energy, organics, liquid). After some discussion the workshop settled on three such environments:
- terrestrial petroleum deposits isolated from liquid water;
- the methane-ethane seas of Titan, and
- CO2 above and below the critical point.
With respect to (2), the team decided after much deliberation that the solubilities and reactivities in the Titan seas were too low for significant chemistry to occur, and so a broader range of environments - informed by Cassini data - were selected for consideration in the next workshop. Environment (1), the petroleum, is of interest provided samples not in intimate contact with water (or at least geologically pasteurized after exposure, followed by isolation). One such potential samples exists in the lab of a workshop participant (Prof. Orphan), but a careful protocol would need to be developed to open and test the sample. Further, there may be existing data from laboratories on petroleum samples that may shed some light on the question of contamination by aqueous organisms. Environment (3) was developed only after discussion about the extent to which planetary modelers needed to be specific about the T-P conditions and geologic settings.
The goals for the September workshop are the following:
- For the petroleum deposits, report on existing published/unpublished analyses of such samples, evaluate signs of aqueous biological contamination, and discuss protocols for sampling for petroleum based life (what to look for?).
- For the Titan environments, report on studies of the potential for surfaces to catalyze reactions and on studies of potential geological/atmospheric processes that might aid reactivity. Follow up on the surprisingly rapid reaction involving organic compounds reported by Hodyss. Develop some examples of autocatalysis that would work in a Titan environment. Investigate the environments of “super-Titans” around other stars and consider the spectral and photometric characteristics of the atmosphere that might be detectable by near-future observations.
- For the CO2, develop some exemplary organic reaction schemes that might lead to autocatalysis. Document terrestrial settings where liquid- or/and supercritical-CO2 is present. Investigate the conditions by which a CO2-rich atmosphere does not lead to Venus-like extreme greenhouse warming by using a 1D Radiative convective transfer model. Also, consider the spectral and photometric signatures of CO2 worlds that might be detectable with near-future observatories.