Merging White Dwarfs, Thermonuclear Supernovae, Other Transients

合并白矮星、热核超新星、其他瞬变

基本信息

批准号：
261946-2013
负责人：
vanKerkwijk, Marten
金额：
$ 3.79万
依托单位：
University of Toronto
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2017
资助国家：
加拿大
起止时间：
2017-01-01 至 2018-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633367
关键词：
Merging White Dwarfs Thermonuclear Supernovae

项目摘要

MERGING WHITE DWARFS, THERMONUCLEAR SUPERNOVAE, AND OTHER TRANSIENTSThe 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?

白矮星、热核超新星和其他瞬变的合并两个白矮星的合并可能会导致壮观的瞬变——热核超新星或吸积引起的中子星塌缩——或者形成奇怪的物体——例如 R CrB 氦巨大的星星。我们最近意识到，由碳和氧组成的两颗白矮星的合并很可能会产生大多数热核超新星，并且与当前的范式相反，这很可能独立于它们的总质量是否超过最大可能的钱德拉塞卡质量而发生。我的建议是发展这个新的研究方向，希望能够回答以下几组问题：什么触发了热核超新星？从观察中，我们能否区分由于钱德拉塞卡附近天体中的高密度引起的点火，或由于亚钱德拉塞卡天体中的高温引起的点火？它是在与另一颗白矮星快速合并时发生的，还是在伴星缓慢吸积时发生的？白矮星合并的结果是什么？通过模拟，合并残余物具有哪些属性？当剩余的圆盘不断增长和旋转演化时会发生什么？有些会引发核逃逸吗？可能会发生爆炸吗？这会产生热核超新星吗？人们可能会想到哪些其他瞬变？自然界中会发生哪些类型的瞬变？理论预测的众多不同的瞬态是否真的发生了？有没有我们想象不到的？对于超新星，我们能看到恒星爆发的激波吗？看到ejecta 与同伴、磁盘或其环境交互吗？