论文标题
D型共生星EF AQL的光谱和X射线观察
Optical spectroscopy and X-ray observations of the D-type symbiotic star EF Aql
论文作者
论文摘要
我们对最近确定的Mira型共生星EF AQL进行了高分辨率光谱和X射线观测。基于使用盐获得的高分辨率光谱，我们确定了系统中热点的温度（$ \ sim $ 55 000 k）和亮度（$ \ sim $ 5.3 $ l_ \ odot $）。光谱中发射线的地层径向速度揭示了化学元件的分层。我们还估计了MIRA供体恒星的质量损失率。我们的迅速观察未在X射线中检测到EF AQL。 X射线观测值的上限为10 $^{ - 12} $ erg cm $^{ - 2} $ s $^{ - 1} $，这意味着EF AQL与到目前为止检测到的最微弱的X射线系统一致。否则，我们用平均UVM2幅度为14.05的UVOT仪器检测到它。在暴露期间，EF AQL大约是0.2 UVM2幅度。对V波段数据的周期图分析显示，由Mira型供体恒星的脉动引起的320.4 $ \ pm $ 0.3 d的改善。这些光谱可应作者的要求提供。
We performed high-resolution optical spectroscopy and X-ray observations of the recently identified Mira-type symbiotic star EF Aql. Based on high-resolution optical spectroscopy obtained with SALT, we determine the temperature ($\sim $55 000 K) and the luminosity ($\sim$ 5.3 $L_\odot$) of the hot component in the system. The heliocentric radial velocities of the emission lines in the spectra reveal possible stratification of the chemical elements. We also estimate the mass-loss rate of the Mira donor star. Our Swift observation did not detect EF Aql in X-rays. The upper limit of the X-ray observations is 10$^{-12}$ erg cm$^{-2}$ s$^{-1}$, which means that EF Aql is consistent with the faintest X-ray systems detected so far. Otherwise we detected it with the UVOT instrument with an average UVM2 magnitude of 14.05. During the exposure, EF Aql became approximately 0.2 UVM2 magnitudes fainter. The periodogram analysis of the V-band data reveals an improved period of 320.4$\pm$0.3 d caused by the pulsations of the Mira-type donor star. The spectra are available upon request from the authors.
