GW170817雙中子星的合併事件之多信使訊號觀測結果揭示了關於核輻射驅動噴流之特性的有趣問題。快中子捕獲(r-process)可以在噴流中發生並合成比鐵還重的元素。合成的產率與噴流本身的特性有關，而核融合產生的熱能同時也會改變噴流特性。本研究對合併後留下的中子星周圍之流體特性進行參數化的流體力學模擬，並研究核加熱對於千新星(kilonovae) 噴流和後續核融合反應的反饋。四個噴流參數被考慮，加熱的比率，注入噴流的半徑，密度分部和初始內能和動能的比例。研究結果發現，相較於未加熱時獲得的值相比，快中子捕獲所造成的加熱反饋可以顯著提高噴流的速度並同時增加噴流的溫度和熵。

The multimessenger detections of the kilonova GW170817 from a merger of two neutron stars reveal several interesting questions in understanding the properties of its radioactively powered ejecta. The r-process nucleosynthesis can take place in this non-spherical ejecta, producing elements heavier than iron. The synthesized yields are sensitive to the ejecta properties, and the nuclear heating feedback
modifies the ejecta properties. Here we parametrize the outflow properties around the merger remnants and investigate the feedback from nuclear heating on the outflow of kilonova ejecta and the follow-up nucleosynthesis via long-term axisymmetric hydrodynamics simulations. In this work, four ejecta parameters are evaluated,
including percentage of heating, injection radius, density distributions, and the internal energy to kinetic energy ratios. We find that r-process heating feedback could significantly enhance the ejecta velocity and enlarge the ejecta temperature and entropy, comparing to the values obtained without heating.

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
摘要 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ii
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . iii
Table of contents . . . . . . . . . . . . . . . . . . . . . . . . .iv
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . v
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . .v
1 Introduction 1
2 Numerical Methods 2
2.1 Ejecta configuration . . . . . . . . . . . . . . . . . . . . . .3
2.2 Parametrized nuclear heating . . . . . . . . . . . . . . . . . .4
3 Results 7
3.1 Ejecta properties . . . . . . . . . . . . . . . . . . . . . . . 7
3.2 Tracer trajectory . . . . . . . . . . . . . . . . . . . . . . . 12
4 Conclusion 19
Reference 20

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