标题： 双氧氖白矮星并合遗迹的演化 显示英文标题

标题： Evolution of double oxygen-neon white dwarf merger remnant

摘要： 双白矮星（WD）并合过程及其合并后的演化在天文学的许多领域都很重要，例如超新星、伽马射线暴、引力波等。 尽管普遍共识认为合并残骸会坍缩形成中子星，但双超大质量白矮星合并残骸的演化结局仍存在争议。 在这项工作中，我们研究了由两个1.10倍太阳质量ONe白矮星并合形成的2.20倍太阳质量残骸的演化。 我们发现，并合后不久，残骸在接近主白矮星表面的位置点燃了近中心的氖燃烧，导致稳定向内传播的氧/氖（O/Ne）火焰。 并合残骸的最终结局对对流边界混合效应非常敏感。 如果这种混合不能阻止O/Ne火焰，火焰将在20年内到达中心，导致形成超钱德拉塞卡质量的硅核，其最终命运可能是通过铁核坍缩超新星形成中子星（NS）。 相比之下，如果对流混合足够有效以防止O/Ne火焰到达中心，则合并残骸将经历电子俘获超新星并形成ONeFe白矮星。 同时，我们发现由于残骸的快速演化，风质量损失过程可能几乎不会改变残骸的最终命运。 我们的结果表明，双ONe白矮星的并合可以形成短寿命的巨大天体，但最终结局（中子星或ONeFe白矮星）受O/Ne火焰中不确定的对流混合的影响。 显示英文摘要

摘要： Double white dwarf (WD) merger process and their post-merger evolution are important in many fields of astronomy, such as supernovae, gamma-ray bursts, gravitational waves, etc. The evolutionary outcomes of double ultra-massive WD merger remnants are still a subject of debate, though the general consensus is that the merger remnant will collapse to form a neutron star. In this work, we investigate the evolution of a 2.20Msun merger remnant stemmed from the coalescence of double 1.10Msun ONe WDs. We find that the remnant ignites off-centre neon burning at the position near the surface of primary WD soon after the merger, resulting in the stable inwardly propagating oxygen/neon (O/Ne) flame. The final outcomes of the merger remnant are sensitive to the effect of convective boundary mixing. If the mixing cannot stall the O/Ne flame, the flame will reach the centre within 20 years, leading to the formation of super Chandrasekhar mass silicon core, and its final fate probably be neutron star (NS) through iron-core-collapse supernova. In contrast, if the convective mixing is effective enough to prevent the O/Ne flame from reaching the centre, the merger remnant will undergo electron capture supernova to form an ONeFe WD. Meanwhile, we find that the wind mass loss process may hardly alter the final fate of the remnant due to its fast evolution. Our results imply that the coalescence of double ONe WDs can form short lived giant like object, but the final outcomes (NS or ONeFe WD) are influenced by the uncertain convective mixing in O/Ne flame.