Optical and ultraviolet observations of a strong flare in the young, single K2 dwarf LQ Hya
Optical and ultraviolet observations of a strong flare in the young, single K2 dwarf LQ Hya
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DOI：
10.1046/j.1365-8711.1999.02373.x
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发表时间：
1998-11
影响因子：
4.8
通讯作者：
D. Montes;S. Saar;A. Cameron;Y. C. U. D. A. U. C. Madrid-Y.-C.-U.-D.-A.-U.-C.-Madrid-2095782423;P. S. University;Harvard-Smithsonian Cfa;U. St.Andrews;I. Vienna
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文献类型：
--
作者：
D. Montes;S. Saar;A. Cameron;Y. C. U. D. A. U. C. Madrid-Y.-C.-U.-D.-A.-U.-C.-Madrid-2095782423;P. S. University;Harvard-Smithsonian Cfa;U. St.Andrews;I. Vienna
我们展示了 1993 年 12 月 22 日非常活跃、年轻、快速旋转的单 K2 矮星 LQ Hya 强烈耀斑期间的高分辨率光学阶梯光谱和 IUE 观测结果。耀斑的初始脉冲阶段开始于世界标准时间 2:42 到 4:07 之间的某个时间，其特征是强烈的光学连续增强和具有宽翼的蓝移发射线。光学色球谱线在大约 5:31 ut 处达到最大强度，此时蓝移消失并且光学连续谱增强急剧下降。此后，谱线发射缓慢减少，谱线逐渐红移，持续至少两个多小时。 Mg II 线的表现类似。尽管数据差距和可能的第二次耀斑使解释不确定，但静态 C IV 通量水平直到 21 小时后才恢复。除了典型的耀斑增强发射线（例如 H α 和 H β）之外，我们还观察到 He I D_3 进入发射状态，以及其他 He I 和几种强中性金属线（例如 Mg I b）中的过量发射（扣除静态光谱后）。远紫外连续谱的耀斑增强通常与 Si I 复合模型一致。我们估计了总耀斑能量，并讨论了一些发射线中看到的广泛成分、不对称性和多普勒频移。
We present high-resolution optical echelle spectra and IUE observations during a strong flare on 1993 December 22 in the very active, young, rapidly rotating, single K2 dwarf LQ Hya. The initial impulsive phase of the flare, which started sometime between 2:42 ut and 4:07 ut, was characterized by strong optical continuum enhancement and blueshifted emission lines with broad wings. The optical chromospheric lines reached their maximum intensity at ≈ 5:31 ut, by which time the blueshift vanished and the optical continuum enhancement had sharply decreased. Thereafter, the line emission slowly decreased and the lines redshift in a gradual phase that lasted at least two more hours. The Mg II lines behaved similarly. Quiescent C IV flux levels were not recovered until 21 h later, though a data gap and a possible second flare make the interpretation uncertain. In addition to the typically flare-enhanced emission lines (e.g., H α and H β), we observe He I D_3 going into emission, plus excess emission (after subtraction of the quiescent spectrum) in other He I and several strong neutral metal lines (e.g., Mg I b). Flare enhancement of the far-ultraviolet continuum generally agrees with an Si I recombination model. We estimate the total flare energy, and discuss the broad components, asymmetries and Doppler shifts seen in some of the emission lines.