论文标题
LIN 358：稳定氢融合极限以上积聚的共生二元
LIN 358: A symbiotic binary accreting above the steady hydrogen fusion limit
论文作者
论文摘要
共生二进制文件是长时间相互作用的二进制文件，由白矮人（WD）通过恒星风从凉爽的巨型恒星中积聚的材料组成。在本文中，我们研究了位于SMC中的共生二进制LIN 358。我们已经观察到LIN 358具有积分磁谱仪的WIFE，并获得了线发射光谱。 With the help of the plasma simulation and spectral synthesis code Cloudy, we have constructed a 2D photo-ionisation model of LIN 358. From comparison with the observations, we have determined the colour temperature of the WD in LIN 358 to be 19 eV, its bolometric luminosity $L = (1.02 \pm 0.15) \times 10^{38}$ erg s$^{-1}$, and the捐赠者星的质量损失率为$ 1.2 \ times 10^{ - 6} $ m $ _ {\ odot} $ yr $^{ - 1} $。假设风材料中的太阳H与HE的比率，LIN 358中积聚的质量分数的下限为0.31。风将叶的质量高质量效率高，这意味着WD在稳定氢融合的上限上方积聚，因此质量增长，最大速率$ \ times 10^{ - 7} $ _ {\ odot} $ _ {\ odot} $ yr yr $^{ - yr $^{ - 1} $。这会导致WD Photosphere扩展，这解释了其低色温度。我们的计算表明，除了供体恒星周围的狭窄锥体外，LIN 358中的偶色材料几乎完全离子化，并且WD发射是自由地逃脱了系统的。但是，由于其低色温度，即使是中等量的中性ISM，这种发射也很容易减弱。我们推测其他共生系统可能在类似的制度下运行，从而解释了观察到的系统的匮乏。
Symbiotic binaries are long period interacting binaries consisting of a white dwarf (WD) accreting material from a cool evolved giant star via stellar winds. In this paper we study the symbiotic binary LIN 358 located in the SMC. We have observed LIN 358 with the integral field spectrograph WiFeS and obtained its line emission spectrum. With the help of the plasma simulation and spectral synthesis code Cloudy, we have constructed a 2D photo-ionisation model of LIN 358. From comparison with the observations, we have determined the colour temperature of the WD in LIN 358 to be 19 eV, its bolometric luminosity $L = (1.02 \pm 0.15) \times 10^{38}$ erg s$^{-1}$, and the mass-loss rate from the donor star to be $ 1.2 \times 10^{-6}$ M$_{\odot}$ yr$^{-1}$. Assuming a solar H to He ratio in the wind material, a lower limit to the accreted mass fraction in LIN 358 is 0.31. The high mass-accretion efficiency of a wind Roche lobe overflow implies that the WD is accreting above the upper boundary of stable hydrogen fusion and thus growing in mass with the maximal rate of $\approx 4 \times 10^{-7}$ M$_{\odot}$ yr$^{-1}$. This causes the WD photosphere to expand, which explains its low colour temperature. Our calculations show that the circumstellar material in LIN 358 is nearly completely ionized except for a narrow cone around the donor star, and that the WD emission is freely escaping the system. However, due to its low colour temperature, this emission can be easily attenuated by even moderate amounts of neutral ISM. We speculate that other symbiotic systems may be operating in a similar regime, thus explaining the paucity of observed systems.
