arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1610.04417astro-ph.SRastro-ph.HE
收藏

大质量双星中的共同包层抛射--对GW150914和GW151226祖先的启示

Common envelope ejection in massive binary stars - Implications for the progenitors of GW150914 and GW151226

M. U. Kruckow, T. M. Tauris, N. Langer, D. Szecsi, P. Marchant, Ph. Podsiadlowski

备注：
13 pages, 7 figures, A&A accepted
发表信息：
A&A 596, A58 (2016)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

最近探测到的一对相对大质量的恒星质量黑洞（BH）合并事件的引力波信号（GW 150914和GW 151226）要求对这种祖系统的形成进行一般性的调查。我们分析了共同的信封（CE）阶段的“传统”的形成通道中的二进制文件，其中第一个形成的紧凑的对象经历了在其演变的伴星的信封内的螺旋和在这个过程中的信封。我们计算了初始质量在4和115 Msun之间的施主恒星的包络结合能，金属丰度为Z=Zsun/2和Z=Zsun/50，并推导出喷射这些包络所需的螺旋物体的最小质量。我们发现CE演化除了产生WD-WD和NS-NS双星外，原则上也可能产生大质量BH-BH系统，其中单个BH组分质量高达~50-60 Msun，特别是对于演化为巨星的施主星。然而，大质量恒星的包层喷射的物理学仍然不确定。我们讨论了能量收支形式的适用性、分岔点的位置、复合能和吸积能作为可能的能量来源，并对膨胀氦核的影响进行了评述。大质量恒星的金属丰度范围很广，初始质量至少为115 Msun，可能会脱落它们的外壳，并在CE演化中幸存下来，这取决于它们的初始轨道参数，类似于具有简并核心的中等质量和低质量恒星的情况。我们的结论是，基于恒星结构的计算，并在通常的简单的能量收支分析的角度来看，像GW 150914和GW 151226事件可能产生的CE通道。然而，对CE后轨道间隔的计算，以及因此估计的LIGO探测率，仍然高度不确定。[删节]

英文摘要：

The recently detected gravitational wave signals (GW150914 and GW151226) of the merger event of a pair of relatively massive stellar-mass black holes (BHs) calls for an investigation of the formation of such progenitor systems in general. We analyse the common envelope (CE) stage of the "traditional" formation channel in binaries where the first-formed compact object undergoes an in-spiral inside the envelope of its evolved companion star and ejects the envelope in that process. We calculate envelope binding energies of donor stars with initial masses between 4 and 115 Msun for metallicities of Z=Zsun/2 and Z=Zsun/50, and derive minimum masses of in-spiralling objects needed to eject these envelopes. We find that CE evolution, besides from producing WD-WD and NS-NS binaries, may, in principle, also produce massive BH-BH systems with individual BH component masses up to ~50-60 Msun, in particular for donor stars evolved to giants. However, the physics of envelope ejection of massive stars remains uncertain. We discuss the applicability of the energy-budget formalism, the location of the bifurcation point, the recombination energy and the accretion energy during in-spiral as possible energy sources, and also comment on the effect of inflated helium cores. Massive stars in a wide range of metallicities and with initial masses up to at least 115 Msun may possibly shed their envelopes and survive CE evolution, depending on their initial orbital parameters, similarly to the situation for intermediate mass and low-mass stars with degenerate cores. We conclude that based on stellar structure calculations, and in the view of the usual simple energy budget analysis, events like GW150914 and GW151226 could possibly be produced from the CE channel. Calculations of post-CE orbital separations, however, and thus the estimated LIGO detection rates, remain highly uncertain. [Abridged]

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑