Réunion d’équipe le 2 juin 2018

The detection of oceans and the characterisation of terrestrial worlds is central to understanding whether other planets are likely habitable, and thus to estimating the probability of life existing on those worlds. The method of polarimetry shows promise for characterisations with advancements in instrumentation in the last decade providing scientists with a means to detect polarised light from the atmospheres of gas giants in spite of a relative lack of funding for this technology in the past.
While previous models of terrestrial planets in polarised light exist, these are often simplified with Lambertian (non-polarising) surfaces, or idyllic atmospheres.
We aim to model a holistic signal which includes complete treatment of ground covers and liquid surfaces, clouds, and self-consistent, realistic atmospheres in combination. The purpose of this is to determine if these signatures are readily distinguishable and measurable with near-future instruments.
Using the VSTAR radiative transfer solver’s updated polarimetric capabilities and the suite of planet outcomes predicted for terrestrial and super Earth worlds (see Meadows 2017 for a review) we produce predictive signatures for habitable and non-habitable small worlds around sun-like stars and M-dwarfs.
We find that in some of these cases detections of the atmosphere and possibly ocean glint is likely only 1-2 orders of magnitude beyond current polarimetric capabilities, suggesting advances in instrumentation over the next decade if akin to the rate of advancement in the last, might make this a viable means of characterisation if noise sources can be well characterised.