M DWARF FLARES FROM TIME-RESOLVED SLOAN DIGITAL SKY SURVEY SPECTRA
M DWARF FLARES FROM TIME-RESOLVED SLOAN DIGITAL SKY SURVEY SPECTRA
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DOI：
10.1088/0004-6256/140/5/1402
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发表时间：
2010-10
期刊：
影响因子：
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通讯作者：
E. Hilton;A. West;S. Hawley;A. Kowalski
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文献类型：
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作者：
E. Hilton;A. West;S. Hawley;A. Kowalski
我们利用一种称为耀斑线指数的新型发射线强度测量方法，从斯隆数字巡天（SDSS）的单个组分光谱中识别出了63个M型矮星上的耀斑。在韦斯特等人的SDSS低质量恒星光谱样本中，大约38000个M型矮星中的每一个都被观测了数次（通常是3 - 5次），每次曝光时间通常为9 - 25分钟。我们的标准使我们能够识别出在曝光过程中表现出非常强的Hα和Hβ发射线强度以及/或者这些谱线有显著变化的耀斑。我们所识别的耀斑具有与经典光谱监测所观测到的耀斑一致的特征。我们发现样本中天体的耀斑占空比从早期M型矮星的0.02%增加到晚期M型矮星的3%。我们还发现，在银河系平面附近的星族中耀斑占空比更大，并且耀斑恒星在空间上比有磁活动但无耀斑的恒星更受限。这表明耀斑频率可能与恒星年龄有关（较年轻的恒星更有可能产生耀斑），并且耀斑恒星比平均的活动星族更年轻。
We have identified 63 flares on M dwarfs from the individual component spectra in the Sloan Digital Sky Survey (SDSS) using a novel measurement of emission-line strength called the Flare Line Index. Each of the ∼38,000 M dwarfs in the SDSS low-mass star spectroscopic sample of West et al. was observed several times (usually 3–5) in exposures that were typically 9–25 minutes in duration. Our criteria allowed us to identify flares that exhibit very strong Hα and Hβ emission-line strength and/or significant variability in those lines throughout the course of the exposures. The flares we identified have characteristics consistent with flares observed by classical spectroscopic monitoring. The flare duty cycle for the objects in our sample is found to increase from 0.02% for early M dwarfs to 3% for late M dwarfs. We find that the flare duty cycle is larger in the population near the Galactic plane and that the flare stars are more spatially restricted than the magnetically active but non-flaring stars. This suggests that flare frequency may be related to stellar age (younger stars are more likely to flare) and that the flare stars are younger than the mean active population.