论文标题
Sun-As-A-Star光谱观察到2021年10月28日太阳喷发的视线速度
Sun-as-a-star spectroscopic observations of the line-of-sight velocity of a solar eruption on October 28, 2021
论文作者
论文摘要
太阳冠状质量射出的传播方向和真实速度，这是其地理效应的最决定性因素之一，很难通过单观测成像观测来确定。在这里，我们表明Sun-As-A-Star光谱观测以及成像观察结果可以使我们能够解决这个问题。利用对太阳能动力学观测站的极端硫酸变化性实验的观察，我们在2021年10月28日的太阳喷发期间发现了极端紫外光谱线中清晰的蓝移二次发射成分。从同时成像观测值中，我们构成了二次组件由flare群体产生的次要组件。我们估计了双高斯拟合方法和红蓝色不对称分析的射出线速度（LOS）速度。两种方法的结果彼此都很好，给出了$ \ sim 423〜 \ rm {km〜s^{ - 1}} $的平均LOS速度。从$ 304 $ Å〜图像系列中，由极端紫外线成像器在船上拍摄的太阳陆地关系天线a（contereo-a）航天器，我们估计了从立体声 - A Viewpoint {the fiewpoint {左右的{km〜rm〜587〜 \ rm〜s { The full velocity of the bulk motion of the ejecta was then computed by combining the imaging and spectroscopic observations, which turns out to be around $596~\rm{km~s^{-1}}$ with an angle of $42.4^\circ$ to the west of the Sun-Earth line and $16.0^\circ$ south to the ecliptic plane.
The propagation direction and true velocity of a solar coronal mass ejection, which are among the most decisive factors for its geo-effectiveness, are difficult to determine through single-perspective imaging observations. Here we show that Sun-as-a-star spectroscopic observations, together with imaging observations, could allow us to solve this problem. Using observations of the Extreme-ultraviolet Variability Experiment onboard the Solar Dynamics Observatory, we found clear blue-shifted secondary emission components in extreme ultraviolet spectral lines during a solar eruption on October 28, 2021. From simultaneous imaging observations, we found that the secondary components are caused by a mass ejection from the flare site. We estimated the line-of-sight (LOS) velocity of the ejecta from both the double Gaussian fitting method and the red-blue asymmetry analysis. The results of both methods agree well with each other, giving an average LOS velocity of the plasma of $\sim 423~\rm{km~s^{-1}}$. From the $304$ Å~image series taken by the Extreme Ultraviolet Imager onboard the Solar Terrestrial Relation Observatory-A (STEREO-A) spacecraft, we estimated the plane-of-sky (POS) velocity from the STEREO-A viewpoint {to be around $587~\rm{km~s^{-1}}$}. The full velocity of the bulk motion of the ejecta was then computed by combining the imaging and spectroscopic observations, which turns out to be around $596~\rm{km~s^{-1}}$ with an angle of $42.4^\circ$ to the west of the Sun-Earth line and $16.0^\circ$ south to the ecliptic plane.
