论文标题
耀斑和CME的特性在EV lac上:可能爆发的细丝
Properties of flares and CMEs on EV Lac: Possible erupting filament
论文作者
论文摘要
耀斑和CME是非常有力的事件,在短时间内弹出能量辐射和颗粒。因此,这些事件可以强烈影响绕这些恒星绕的行星。这与M-Star的行星特别相关,因为这些恒星在演变中长时间保持活跃,并且在短距离处可能可居住的行星轨道。不幸的是,对于M-Star中的耀斑与CME之间的关系尚无多知识,因为到目前为止,在M-Star中只观察到了很少的CME。为了了解M-Star上的耀斑和CME的更多信息,我们以高分辨率在高分辨率下通过光谱监测了活动的M-Star EV lac。我们发现在光谱监测的127小时内,HALPHA中的1.6e31至1.4e32 ERG之间的能量在45小时在457小时的苔丝观察期间,能量在6.3e31至1.1E33 ERG之间。统计分析表明,苔丝带中连续通量与HALPHA中发出的能量的比率为10.408 +/- 0.026。对光谱的分析表明,在某些耀斑的冲动阶段,He II4686Å线的通量增加。在三个大耀斑中,我们检测到温度在6 900至23 000 K之间的连续源。在没有耀斑的情况下,我们发现明确的CME事件,表明这些事件在活动的M-Star中必须非常罕见。但是,在一个相对较弱的事件中,我们在〜220 km/s的Balmer线中发现了一个不对称性,我们将其解释为爆发丝的标志。
Flares and CMEs are very powerful events in which energetic radiation and particles are ejected within a short time. These events thus can strongly affect planets that orbit these stars. This is particularly relevant for planets of M-stars, because these stars stay active for a long time during their evolution and yet potentially habitable planets orbit at short distance. Unfortunately, not much is known about the relation between flares and CMEs in M-stars as only very few CMEs have so far been observed in M-stars. In order to learn more about flares and CMEs on M-stars we monitored the active M-star EV Lac spectroscopically at high resolution. We find 27 flares with energies between 1.6E31 and 1.4E32 erg in Halpha during 127 hours of spectroscopic monitoring and 49 flares with energies between 6.3E31 and 1.1E33 erg during the 457 hours of TESS observation. Statistical analysis shows that the ratio of the continuum flux in the TESS-band to the energy emitted in Halpha is 10.408 +/- 0.026. Analysis of the spectra shows an increase in the flux of the He II 4686 Å line during the impulsive phase of some flares. In three large flares, we detect a continuum source with a temperature between 6 900 and 23 000 K. In none of the flares we find a clear CME event indicating that these must be very rare in active M-stars. However, in one relatively weak event, we found an asymmetry in the Balmer lines of ~220 km/s which we interpret as a signature of an erupting filament.