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A unified theory of cataclysmic variable evolution from feedback-dominated numerical simulations
Nature Astronomy ( IF 12.9 ) Pub Date : 2020-03-23 , DOI: 10.1038/s41550-020-1062-y
Yael Hillman , Michael M. Shara , Dina Prialnik , Attay Kovetz

The envelopes accreted by white dwarf stars from their hydrogen-rich companions1 experience thermonuclear-powered runaways2,3 observed as classical nova eruptions4,5 peaking at 105–106 solar luminosities6,7,8,9. Virtually all nova progenitors—‘nova-like variables’—exhibit high mass transfer rates to their white dwarfs before and after an eruption10. Surprisingly, 10–1,000 times lower mass transfer rate11 binaries, exhibiting accretion-powered ‘dwarf nova’ outbursts12, exist at identical orbital periods. Nova shells surrounding dwarf novae13,14,15,16 demonstrate that at least some novae metamorphize into dwarf novae17,18, though the mechanisms and timescales governing mass transfer rate variations are poorly understood. Here, we report simulations of the multi-Gyr evolution of novae modelling every eruption’s thermonuclear runaway, mass and angular momentum losses, feedback due to irradiation and variable mass transfer rate, and orbital size and period changes. These feedback-dominated simulations reproduce the observed range of mass transfer rates at a given orbital period, with large and cyclic kyr–Myr timescale changes. They also demonstrate Myr-long deep hibernation (complete stoppage of mass transfer), but only in short-period binaries; that initially different binaries converge to become nearly identical systems; low-mass-transfer-rate dwarf novae occasionally generate novae; and that the masses of white dwarfs decrease monotonically, but only slightly while their red dwarf companions are consumed.



中文翻译:

基于反馈控制的数值模拟的灾变变量演化的统一理论

白矮星从富含氢的同伴1所吸收的包膜经历了由热核动力的失控2,3,这是经典的新星爆发4,5在10 5 –10 6太阳光度6,7,8,9达到峰值。几乎所有新星祖先(“新星样变量”)在喷发前后都表现出很高的向白矮星的传质速率10。出人意料的是,在相同的轨道周期内,存在着质量增加速率低10-1,000倍的双星11,它们具有增生动力“矮新星”爆发12。环绕矮新星的新星壳13,14,15,16证明至少有一些新星变质为矮新星17,18,尽管对传质速率变化的机制和时标知之甚少。在这里,我们报告了新星多吉尔演化的模拟过程,模拟了每次喷发的热核失控,质量和角动量损失,由于辐照和可变质量传递速率而产生的反馈以及轨道大小和周期变化。这些以反馈为主导的模拟在一定的轨道周期内重现了观察到的传质速率范围,并且有较大且周期性的吉尔-米尔时间尺度变化。它们还显示了Myr长时间的深度休眠(完全停止传质),但仅在短期二进制文件中;最初不同的二进制文件汇合成为几乎相同的系统;低质量转移率的矮新星偶尔会产生新星;而且白矮星的质量单调减少,

更新日期:2020-04-24
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