AI 中文总结
研究首次通过三维流体动力学模拟结合真实物态方程，揭示潮汐瓦解事件中氢复合与分子氢形成注入的能量会加速残骸流膨胀，为潮汐瓦解事件后期建模提供了合理初始条件，有助于探究其辐射起源。
AI 中文摘要
在潮汐瓦解事件中，产生的残骸流因潮汐拉伸而绝热冷却。随着温度下降，气体预计会发生化学过程，这可能向残骸流释放热能，进而影响后续的气体演化。我们首次通过三维流体动力学模拟结合真实的物态方程，详细研究了这一效应及其对残骸流早期演化的动力学影响。我们发现，瓦解发生数天后，氢复合和分子氢形成所注入的能量会导致残骸流厚度快速增长。在受束缚的残骸中，该效应会在气体到达远心点前终止残骸流的自引力束缚。因此，最大残骸流厚度的增长倍数范围为：受束缚最强的气体增长数倍，近抛物线轨道气体增长数十倍，在质量回落率峰值附近达到约30 R☉。我们讨论了这种加速的残骸流膨胀如何影响气体的后续演化，估算了未受束缚残骸中由复合提供的光度，并评估了非理想磁流体动力学效应的潜在影响。通过表征残骸流在返回近心点前的热力学和流体动力学性质，我们的结果为自洽建模潮汐瓦解事件的后期阶段提供了符合物理规律的初始条件，为揭示其观测到的辐射的物理起源提供了可行途径。
英文摘要
During a tidal disruption event, the resulting debris stream cools down adiabatically due to the tidal stretching. As the temperature drops, the gas is expected to undergo chemical processes, which can release thermal energy into the stream, potentially affecting the subsequent gas evolution. For the first time, we investigate in detail this effect and its dynamical impact on the early-time evolution of the stream by making use of three dimensional hydrodynamic simulations coupled with a realistic equation of state. We find that a few days after disruption, the energy injected by hydrogen recombination and molecular hydrogen formation causes the stream thickness to grow much more rapidly. In the bound debris, this effect stops the stream's confinement by self-gravity before the gas reaches apocentre. As a result, the maximum stream thickness increases by a factor that ranges from a few, for the most bound gas, to a few tens for the near-parabolic gas, reaching $\approx 30 \, R_{\star} $ around the peak of the mass fallback rate. We discuss how this accelerated stream expansion may affect the subsequent evolution of the gas, estimate the luminosity powered by recombination in the unbound debris, and evaluate the potential influence of non-ideal magneto-hydrodynamic effects. By characterizing the thermodynamic and hydrodynamic properties of the stream before its return near pericentre, our results provide physically motivated initial conditions to self-consistently model the later stages of tidal disruption events, offering a promising pathway to unveiling the physical origins of their observed emission.
CommentsSubmitted to MNRAS. Comments are welcome!
