from non-gravitational force caused by outgassing (Davidsson & Gutiérrez 2005), the evolution of morphology of the nucleus influenced by the insolation-induced activity (Keller et al. 2015; Groussin et al. 2025), interpretation of the measured water production (Hu et al. 2017; Blum et al. 2017; Attree et al. 2019), and the explanation of distinct activity phenomena such as the shortlived outbursts from fractured terrains (Skorov et al. 2016). To further improve model fidelity, it is necessary to consider additional complex physical mechanisms, such as the behavior of volatile transport in the nucleus given rise by its porosity, the deposition of gas on dust particles and so on (De Sanctis et al. 1999; Davidsson & Skorov 2002; Gortsas et al. 2011; González et al. 2014; Hu & Shi 2021). Traditionally, thermophysical models are realized by numerical treatment based on the finite-difference technique, such as the Crank-Nicolson method utilized by Hu et al. (2017). However, it usually requires relatively high computation cost due to the iterative calculations performed on a large time-space grids, leads to limited efficiency in related studies, posing challenges for practical implementation. Firstly, the inverse extraction of physical parameters automatically from observational data is a difficult problem, typically, the forward trial-and-error method is utilized (Keller et al. 2015; Hu et al. 2017; Attree et al. 2019). Besides, Combi et al. (2019, 2021b, 2023) are continuously updating the water production rate curves of numerous comets, directly solving the thermal models through numerical simulation to analyze these data is clearly a highly challenging task. The orbital evolution of the comet influenced by non-gravitational acceleration from sublimation (Davidsson & Gutiérrez 2005; Attree et al. 2019; Jewitt et al. 2020), as well as the changes in
Comets are active small solar system bodies. When approaching the Sun, their nuclei get heated up, and volatile ices therewithin sublimate, dragging dust particles alongside to form detectable coma and tails (Whipple 1950). The activity of comets is an intriguing topic, as it provides insights into the formation and evolution of comets, such as the cyclical variations in the relative abundance of water ice keeping the comet ‘alive’ (De Sanctis et al. 2015; Shi et al. 2018), heat transport and ice sublimation reflecting properties of the upper-most layer of cometary nucleus (Gulkis et al. 2015), seasonal effect of ice sublimation inducing various topographical changes (El-Maarry et al. 2015; Tang et al. 2024). It can also help us to understand the possibility for comets to have delivered water to Earth (Mandt et al. 2024). Within ∼3 au, water vapor is the predominant species in outgassing (Hässig et al. 2015; Läuter et al. 2020). The water production rate and the dust production rate are primary indicators for characterizing cometary activity and its variations. The modelling of water and dust production requires simulating the thermophysical processes, taking into account the orbit and the shape of the nucleus, and its various physical properties. There are variations in the thermophysical models for different aims (Watson et al. 1963; Cowan & A’Hearn 1979; Weissman & Kieffer 1981). They have been applied in quantitative analysis of the impact of parameters on water ice activity (Marshall et al. 2019), as well as investigating mechanisms behind the disruption of a cometary nucleus (Steckloff et al. 2015). For interpreting observational data, more realistic thermophysical models are required, such as the inversion of 67P’s physical properties
Article number, page 1 of 13 its spin state due to the non-gravitational torque (Keller et al.