arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2408.12937astro-ph.SRastro-ph.HE
收藏

亚声速边界层中的流体动力学剪切混合及其在经典新星热核爆炸中的作用

Hydrodynamical shear mixing in subsonic boundary layers and its role in the thermonuclear explosion of classical novae

Marco Bellomo, Steven N. Shore, Jordi José

AI总结:

本研究将临界层不稳定性应用于白矮星边界层,通过PLUTO和SHIVA代码模拟亚声速剪切混合对经典新星热核失控的影响,发现该混合机制显著缩短了达峰时间、增加了抛射质量与速度,并使7Li产率降低约一个数量级。

摘要:

在经典新星中,白矮星(WD)包层与周围吸积盘之间的过渡区,即边界层,是一个具有强耗散和强涡度的区域。在这个强剪切层中,富氢吸积气体预计会与下方的WD最外层发生混合,因此经典新星中热核失控(TNR)爆发的条件将不同于标准处理中对爆发起始及随后混合的处理。我们将临界层不稳定性(CLI)应用于激变双星中质量吸积WD的吸积H/He区与富C/O或富O/Ne外层之间的边界,然后将所得结构作为新星爆发一维核流体动力学模拟的输入。我们使用可压缩流体动力学代码PLUTO,在适合内盘以及0.8太阳质量CO WD、1.25太阳质量CO和ONe WD的条件下,模拟了二维亚声速混合过程。随后将得到的化学丰度剖面导入一维核流体动力学代码SHIVA,以模拟TNR的触发、增长率及随后的包层抛射。我们发现,深部剪切驱动混合改变了TNR的触发与发展。具体而言,达到峰值温度的时间显著缩短,抛射质量和抛射物的最大速度远大于当前处理方法的结果。7Li的产率相比当前处理方法降低了约一个数量级。

英文摘要:

The transition zone between the white dwarf (WD) envelope and a circumstellar accretion disk in classical novae, the boundary layer, is a region of strong dissipation and intense vorticity. In this strongly sheared layer, the hydrogen-rich accreted gas is expected to mix with the underlying WD outermost layers so the conditions for the onset of the thermonuclear runaway (TNR) in classical nova will be different from the the standard treatment of the onset and subsequent mixing. We applied the critical layer instability (CLI) to the boundary between a disk-accreted H/He zone and the C/O - or O/Ne - rich outer layers of a mass-accreting WD in a cataclysmic binary and then used the resulting structure as input to one-dimensional nuclear-hydrodynamic simulations of the nova outburst. We simulated the subsonic mixing process in two dimensions for conditions appropriate for the inner disk and a CO 0.8 solar mass and CO and ONe 1.25 solar mass WDs using the compressible hydrodynamics code PLUTO. The resulting compositional profile was then imported into the one-dimensional nuclear-hydrodynamics code SHIVA to simulate the triggering and growth rate for the TNR and subsequent envelope ejection. We find that the deep shear-driven mixing changes the triggering and development of the TNR. In particular, the time to reach peak temperature is significantly shorter, and the ejected mass and maximum velocity of the ejecta substantially greater, than the current treatment. The 7Li yield is reduced by about an order of magnitude relative to the current treatments.

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。

↑