The accretion of material onto young protostars is accompanied by the launching of outflows. Observations show that accretion, and therefore also outflows, are episodic. However, the effects of episodic outflow feedback on the core-scale are not well understood. We have performed 88 Smoothed Particle Hydrodynamic simulations of turbulent dense $1 \, \mathrm{M}_{\odot}$ cores, to study the influence of episodic outflow feedback on the stellar multiplicity and the star formation efficiency (SFE). Protostars are represented by sink particles, which use a sub-grid model to capture stellar evolution, inner-disc evolution, episodic accretion and the launching of outflows. By comparing simulations with and without episodic outflow feedback, we show that simulations with outflow feedback reproduce the binary statistics of young stellar populations, including the relative proportions of singles, binaries, triples, etc. and the high incidence of twin binaries with $q\geq 0.95$; simulations without outflow feedback do not. Entrainment factors (the ratio between total outflowing mass and initially ejected mass) are typically $\sim 7\pm 2$, but can be much higher if the total mass of stars formed in a core is low and/or outflow episodes are infrequent. By decreasing both the mean mass of the stars formed and the number of stars formed, outflow feedback reduces the SFE by about a factor of 2 (as compared with simulations that do not include outflow feedback).

中文翻译：

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偶发流出反馈对恒星多样性和恒星形成效率的影响

物质在年轻的原恒星上的吸积伴随着外流的发射。观察表明，吸积和流出都是偶发的。然而，情节流出反馈对核心尺度的影响尚不清楚。我们已经对湍流密集 $1 \, \mathrm{M}_{\odot}$ 核心进行了 88 次平滑粒子流体动力学模拟，以研究偶发流出反馈对恒星多样性和恒星形成效率 (SFE) 的影响。原恒星由汇粒子表示，它们使用子网格模型来捕捉恒星演化、盘内演化、情节吸积和外流的发射。通过比较有和没有情节流出反馈的模拟，我们表明有流出反馈的模拟再现了年轻恒星群体的二元统计数据，包括单身、二元、三元等的相对比例以及$q\geq 0.95$的孪生二元的高发生率；没有流出反馈的模拟没有。夹带因子（总流出质量与初始喷射质量之间的比率）通常为 $\sim 7\pm 2 $，但如果核心中形成的恒星总质量较低和/或流出事件不频繁，则夹带因子可能会更高。通过减少形成的恒星的平均质量和形成的恒星数量，流出反馈将 SFE 降低了大约 2 倍（与不包括流出反馈的模拟相比）。夹带因子（总流出质量与初始喷射质量之间的比率）通常为 $\sim 7\pm 2 $，但如果核心中形成的恒星总质量较低和/或流出事件不频繁，则夹带因子可能会更高。通过减少形成的恒星的平均质量和形成的恒星数量，流出反馈将 SFE 减少了大约 2 倍（与不包括流出反馈的模拟相比）。夹带因子（总流出质量与初始喷射质量之间的比率）通常为 $\sim 7\pm 2 $，但如果核心中形成的恒星总质量较低和/或流出事件不频繁，则夹带因子可能会更高。通过减少形成的恒星的平均质量和形成的恒星数量，流出反馈将 SFE 降低了大约 2 倍（与不包括流出反馈的模拟相比）。