标题： 低质量接触双星：极端低质量比下的轨道稳定性 显示英文标题

标题： Low Mass Contact Binaries: Orbital Stability at Extreme Low Mass Ratios

摘要： 随着接触双星系统光变曲线解的数量不断增加，越来越多的潜在明亮红新星前身天体被报告出来。然而，目前仍只有一个确认的事件。在本研究中，我们对考虑恒星内部组成（金属丰度）和年龄对转动半径演化的影响以及其对接触双星不稳定质量比的影响的接触双星系统的轨道稳定性进行了全面的回顾。我们发现，金属丰度和年龄对轨道稳定性都有独立的影响，金属贫乏和较老的系统更加稳定。年龄和金属丰度的综合影响非常显著，以至于对于大多数主星质量为太阳质量或更大的系统，它们已经经历了主序星寿命的一半或更多，其不稳定质量比处于次星低于氢融合质量限制的水平。我们发现，从目前可用的解中，我们无法有把握地将任何系统指定为不稳定的。尽管我们识别出8个潜在的红新星前身天体，但它们都存在方法论或天体物理学上的问题，这降低了我们将它们指定为潜在合并候选者的信心。 显示英文摘要

摘要： With the ever-increasing number of light curve solutions of contact binary systems increasing number of potential bright red nova progenitors are being reported. There remains, however, only one confirmed event. In the present study we undertake a comprehensive review of orbital stability of contact binary systems considering the effects of the stellar internal composition (metallicity) and age on the evolution of the gyration radius and its effect on the instability mass ratio of contact binaries. We find that both metallicity and age have an independent effect on orbital stability with metal poor and older systems being more stable. The combined effects of age and metallicity are quite profound such that for most systems with primaries of solar mass or greater which are halfway or more through the main sequence lifespans have instability mass ratio at levels where the secondary component would be below the hydrogen fusion mass limit. We find that from the currently available solutions we cannot confidently assign any system as unstable. Although we identify 8 potential red nova progenitors all have methodological or astrophysical concerns which lower our confidence in designating any of them as potential merger candidates.