Evolutionary Exobiology II: investigating biological potential of synchronously-rotating worlds

Abstract

AbstractPlanets that orbit M-class dwarf stars in their habitable zones are expected to become tidally-locked in the first billion years of their history. Simulations of potentially habitable planets orbiting K and G-class stars also suggest that many will become tidally-locked or become pseudo-synchronous rotators in a similar time frame where certain criteria are fulfilled. Simple models suggest that such planets will experience climatic regions organized in broadly concentric bands around the sub-stellar point, where irradiation is maximal. Here, we develop some of the quantitative, as well as the qualitative impacts of such climate on the evolutionary potential of life on such worlds, incorporating the effects of topography and ocean currents on potential biological diversity. By comparing atmospheric circulation models with terrestrial circulation and biological diversity, we are able to construct viable thought models of biological potential. While we await the generation of atmospheric circulation models that incorporate topography and varying subaerial landscape, these models can be used as a starting point to determine the overall evolutionary potential of such worlds. The planets in these thought-models have significant differences in their distribution of habitability that may not be apparent from simple climate modelling.