周期性新星天蝎座V745热冲击波的准直和不对称性
Collimation and asymmetry of the hot blast wave from the recurrent nova V745 Scorpii
摘要：
周期性共生新星V745 Sco于2014年2月6日爆炸，并于2月22日和23日由钱德拉X射线天文台透射光栅光谱仪观测到。到那时，超软源阶段已经结束，钱德拉光谱与温度超过10^7 K的高温激波加热的星周介质的辐射一致。X射线谱线轮廓比球对称冲击波的预期峰值更尖锐，零强度时的全宽约为2400 km/s，半峰全宽为1200 +/- 30 km/s，平均净蓝移为165 +/- 10 km/s。红色的线条翅膀越来越多地被残骸中的物质吸收到更长的波长。我们的结论是，冲击波是由一个非球面的拱星介质中，赤道密度增强发挥了作用，在早期的共生新星爆炸雕刻。主要的X射线发射物质的膨胀靠近天平面，与近距离观测到的轨道最一致，将爆炸波分析模型与X射线光谱、雨燕观测和近红外线宽度进行比较，表明爆炸能量约为10 ^43 erg，并确认喷射出的质量约为10^-7 Msun。损失的总质量比引发爆炸所需的吸积质量低一个数量级，表明白矮星正在获得质量，是超新星1a型的祖先候选者。
英文摘要：
The recurrent symbiotic nova V745 Sco exploded on 2014 February 6 and was observed on February 22 and 23 by the Chandra X-ray Observatory Transmission Grating Spectrometers. By that time the supersoft source phase had already ended and Chandra spectra are consistent with emission from a hot, shock-heated circumstellar medium with temperatures exceeding 10^7K. X-ray line profiles are more sharply peaked than expected for a spherically-symmetric blast wave, with a full width at zero intensity of approximately 2400 km/s, a full width at half maximum of 1200 +/- 30 km/s and an average net blueshift of 165 +/- 10 km/s. The red wings of lines are increasingly absorbed toward longer wavelengths by material within the remnant. We conclude that the blast wave was sculpted by an aspherical circumstellar medium in which an equatorial density enhancement plays a role, as in earlier symbiotic nova explosions. Expansion of the dominant X-ray emitting material is aligned close to the plane of the sky and most consistent with an orbit seen close to face-on. Comparison of an analytical blast wave model with the X-ray spectra, Swift observations and near-infrared line widths indicates the explosion energy was approximately 10^43 erg, and confirms an ejected mass of approximately 10^-7 Msun. The total mass lost is an order of magnitude lower than the accreted mass required to have initiated the explosion, indicating the white dwarf is gaining mass and is a supernova Type 1a progenitor candidate.
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