论文标题
Lamost在M型恒星上观察到的H $α$线轮廓的宽阔和红向不对称。
Broadening and redward asymmetry of H$α$ line profiles observed by LAMOST during a stellar flare on an M-type star
论文作者
论文摘要
恒星耀斑的特征是恒星大气中电磁辐射的突然增强。到目前为止，我们对恒星耀斑的大部分理解都来自光度观测，无法检测到耀斑区域的血浆运动。从Lamost DR7的光谱数据来看，我们发现了一种恒星耀斑，其特征是冲动增加，其特征是M4型星的H $α$线强度逐渐下降，并且估计通过H $α$辐射的总能量为10^{33^{33} $ erg。 H $α$线在耀斑期间似乎具有VOIGT曲线，这可能是由于电子密度的急剧增加而引起的急剧压力扩大，并且由于发生了强烈的非热加热而引起的宽敞性宽阔。在H $α$线强度的冲动增加之后，在H $α$线轮廓的红翼上已经确定了明显的增强。红翼增强功能对应于等离子体以100 $ -200 km s $^{ - 1} $的速度从地球上移开。根据目前的太阳耀斑知识，这种红翼的增强可能起源于：（1）耀斑驱动的冠状降雨，（2）色球凝结，或（3）（3）丝/突出爆发，这些丝/突出爆发要么具有非种族的向后传播，要么具有强烈的磁抑制。估计移动等离子体的总质量为$ 10^{15} $ kg。
Stellar flares are characterized by sudden enhancement of electromagnetic radiation in stellar atmospheres. So far much of our understanding of stellar flares comes from photometric observations, from which plasma motions in flare regions could not be detected. From the spectroscopic data of LAMOST DR7, we have found one stellar flare that is characterized by an impulsive increase followed by a gradual decrease in the H$α$ line intensity on an M4-type star, and the total energy radiated through H$α$ is estimated to be on the order of $10^{33}$ erg. The H$α$ line appears to have a Voigt profile during the flare, which is likely caused by Stark pressure broadening due to the dramatic increase of electron density and/or opacity broadening due to the occurrence of strong non-thermal heating. Obvious enhancement has been identified at the red wing of the H$α$ line profile after the impulsive increase of the H$α$ line intensity. The red wing enhancement corresponds to plasma moving away from the Earth at a velocity of 100$-$200 km s$^{-1}$. According to the current knowledge of solar flares, this red wing enhancement may originate from: (1) flare-driven coronal rain, (2) chromospheric condensation, or (3) a filament/prominence eruption that either with a non-radial backward propagation or with strong magnetic suppression. The total mass of the moving plasma is estimated to be on the order of $10^{15}$ kg.
