Collapsars as a major source of r-process elements
Collapsars as a major source of r-process elements
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DOI：
10.1038/s41586-019-1136-0
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发表时间：
2018-09
期刊：
影响因子：
64.8
通讯作者：
D. Siegel;J. Barnes;B. Metzger
中科院分区：
文献类型：
--
作者：
D. Siegel;J. Barnes;B. Metzger
在中子星合并中，通过快速中子俘获（r过程）产生元素在理论上是可以预期的，并且得到了引力波事件GW 170817的多信使观测的支持：这种生产途径原则上足以解释宇宙中大多数r过程元素。对伴随着GW 170817的千诺瓦的分析表明，来自新诞生的黑洞周围形成的残余吸积盘的延迟流出是该事件重r过程物质的主要来源。类似的吸积盘预计也会形成在超新星（由超新星引发的快速旋转的大质量恒星的坍缩）中，之前人们推测它会产生r-过程元素。最近在矮星系网座II中观测到的富含此类元素的恒星，以及在较长的时间尺度上银河系相对于铁的铕化学富集，与中子星合并相比，更符合罕见的超新星在低恒星金属丰度下的行为。在这里，我们报告的模拟表明，Eksar吸积盘产生足够的r-过程元素来解释观测到的宇宙中的丰度。虽然这些超新星比中子星合并更罕见，但每次事件喷出的大量物质弥补了较低的发生率。我们计算出，类星体可能提供宇宙中80%以上的r过程内容。
The production of elements by rapid neutron capture (r-process) in neutron-star mergers is expected theoretically and is supported by multimessenger observations, –of gravitational-wave event GW170817: this production route is in principle sufficient to account for most of the r-process elements in the Universe. Analysis of the kilonova that accompanied GW170817 identified,delayed outflows from a remnant accretion disk formed around the newly born black hole, , –as the dominant source of heavy r-process material from that event,. Similar accretion disks are expected to form in collapsars (the supernova-triggering collapse of rapidly rotating massive stars), which have previously been speculated to produce r-process elements,. Recent observations of stars rich in such elements in the dwarf galaxy Reticulum II, as well as the Galactic chemical enrichment of europium relative to iron over longer timescales,, are more consistent with rare supernovae acting at low stellar metallicities than with neutron-star mergers. Here we report simulations that show that collapsar accretion disks yield sufficient r-process elements to explain observed abundances in the Universe. Although these supernovae are rarer than neutron-star mergers, the larger amount of material ejected per event compensates for the lower rate of occurrence. We calculate that collapsars may supply more than 80 per cent of the r-process content of the Universe.