Serpentinization in the thermal evolution of icy Kuiper belt objects in the early Solar system

Abstract

Here we present an improved algorithm to model the serpentinization process in planetesimals in the early Solar system. Although it is hypothesized that serpentinization-like reactions played an important role in the thermal evolution of planetesimals, few and restricted models are available in this topic. These processes may be important as the materials involved were abundant in these objects. Our model is based on the model by (Gobi & Kereszturi 2017), and contains improvements in the consideration of heat capacities and lithospheric pressure, and in the calculation of the amount of interfacial water. Comparison of our results with previous calculations shows that there are significant differences in the e.g. the serpentinization time -- the time necessary to consume most of the reactants at specific initial conditions -- or the amount of heat produced by this process. In a simple application we show that in icy bodies, under some realistic conditions, below the melting point of water ice, serpentinization reaction using interfacial water may be able to proceed and eventually push the local temperature above the melting point to start a 'runaway' serpentinization. According to our calculations in objects with radii R $\gtrsim$ 200 km serpentinization might have quickly reformed nearly the whole interior of these bodies in the early Solar system.