Merging White Dwarfs, Thermonuclear Supernovae, Other Transients

合并白色、热核超新星和其他瞬变 两颗白色矮星的合并可能会导致一个壮观的瞬间--热核超新星或吸积诱导坍缩成中子星星--或者形成奇怪的物体--比如R CrB氦巨星。 我们最近意识到，由碳和氧组成的两颗白色矮星的合并可能会产生大多数热核超新星，而且与目前的范式相反，这可能会发生，而不管它们的总质量是否超过最大可能值，即克拉塞卡质量。 我的建议是发展这个新的研究方向，希望能回答以下几组问题： 是什么触发了热核超新星？从观测结果来看，我们是否能够区分出在一个近阿格拉塞卡天体中由于高密度而点火，或者在一个亚阿格拉塞卡天体中由于高温而点火？它是发生在与另一颗白色矮星的快速合并中，还是发生在从伴星缓慢吸积的过程中？ 白矮星合并的结果是什么？通过模拟，合并残余物有什么性质？ 当剩余的盘吸积和旋转演化时会发生什么？ 一些会点燃核失控？爆炸会发生吗？ 这会产生热核超新星吗？ 还能有什么其他的瞬变现象呢？ 自然界中会发生哪些类型的瞬变？理论预测的大量不同的瞬变现象真的发生了吗？有没有我们没有想到的？对于超新星，我们能看到从星星爆发出来的冲击波吗？看到喷出物与伴星、圆盘或其环境相互作用了吗？

MERGING WHITE DWARFS, THERMONUCLEAR SUPERNOVAE, AND OTHER TRANSIENTS The merger of two white dwarfs can lead to a spectacular transient -- a thermonuclear supernova or accretion induced collapse to a neutron star -- or the formation of strange objects -- such as the R CrB helium giant stars. We recently realized that mergers of two white dwarfs made of carbon and oxygen might well produce most thermonuclear supernovae, and that this would, contrary to the current paradigm, likely happen independently of whether or not their total mass exceeds the maximum possible, Chandrasekhar mass. My proposal is to develop this new research direction, hoping to answer the following sets of questions: What triggers thermonuclear supernovae? From observations, can we distinguish ignition due to high density in a near-Chandrasekhar object, or due to high temperature in a sub-Chandrasekhar one? Does it happen in a fast merger with another white dwarf, or during slow accretion from a companion? What are the outcomes of white-dwarf mergers? Using simulations, what properties do merger remnants have? What happens as remaining disks accrete and spins evolve? Will some ignite nuclear runaways? Might detonations follow? Would this produce thermonuclear supernovae? What other transients might one expect? What types of transients occur in Nature? Do the multitudes of different transients predicted by theory actually occur? Are there ones we failed to imagine? For supernovae, can we see the shock break out of the star? See ejecta interact with a companion, a disk, or its environment?