Role of serpentinization in the thermal and connected mineral evolution of planetesimals – evaluating possible consequences for exoplanetary systems

This work gives an overview on the general consequences of serpentinization occurring in the planetesimals of any planetary system. These processes were studied by numerical simulations and the model used – based on earlier works – was developed by implementing the effect of interfacial water. As liquid water is fundamentally required for serpentinization, previous simulations considered only such cases when the initial temperature inside the planetesimal was above the melting point of ice thus neglecting the effect of microscopic water layer completely. However, our results show that it must be taken into account and since it facilitates the reaction to occur at temperatures even as low as 200 K – at which bulk liquid water is completely absent – it substantially broadens the initiation of this alteration regarding the range of possible objects. Investigating the effect of changing the initial parameters helps examine the serpentinization in more general terms. Consequently, the findings described here are ubiquitous and can be applied to any exoplanetary system, even if the initial conditions differ considerably from those that were characteristic to our early Solar system. As a first step towards the generalization of such heating processes, we evaluate the role of composition, starting temperature, porosity and planetesimal size on this heating effect. Besides heat generated by decay of radioactive nuclei, serpentinization should be considered as a ‘universal process’ in the thermal evolution of planetesimals, and variations of parameters considered in this model might provide an insight into differences between objects in various protoplanetary discs.