The influence of external factors on surface regimes of terrestrial planets

Convective mantle flow in terrestrial planets is governed by a temperature- and pressure-
dependent rheology. This results in a stagnant-lid regime observed on most terrestrial planets.
Plastic deformation can lead to breaking of the strong upper lithosphere, which resembles plate
tectonics on Earth. With Venus being the most Earth-like planet we can closely study, identifying
the factors that led to the apparent absence of plate tectonics on Venus is vital in understanding
the evolution of rocky exoplanets in general.

In order to determine the likelihood of plate tectonics, we investigate the influence of internal and
external planetary factors, mainly surface temperature and yield stress. We employ a viscoplastic
rheology in a 2D-spherical annulus geometry. The models are evaluated by computing common
diagnostic values used to recognize plate-like surface deformation. The goal of this study is to
identify key planetary factors for the occurrence or absence of plate tectonics.